Publications

@article{deka2022electric,

title = {Electric field induced parametric excitation of exchange magnons in a CoFeB/MgO junction},

author = {A Deka and Bivas Rana and R Anami and K Miura and H Takahashi},

doi = {https://doi.org/10.1103/PhysRevResearch.4.023139},

year  = {2022},

date = {2022-05-20},

journal = {Physical Review Research},

volume = {4},

number = {2},

pages = {023139},

abstract = {Inspired by the success of field-effect transistors in electronics, electric field controlled magnetization dy-namics has emerged as an important integrant in low-power spintronic devices. Here, we demonstrate electricfield induced parametric excitation for CoFeB/MgO junctions by using interfacial in-plane magnetic anisotropy(IMA). When the IMA and the external magnetic field are parallel to each other, magnons are efficiently excitedby electric field induced parametric resonance. The corresponding wavelengths are estimated to be tuned downto  exchange  interaction  length  scales  by  changing  the  input  power  and  frequency  of  the  applied  voltage.  Ageneralized phenomenological model is developed to explain the underlying role of the electric field torque.Electric field control of IMA is shown to be the origin for excitation of both uniform and parametric resonancemodes  in  the  in-plane  magnetized  sample,  a  crucial  element  for  purely  electric  field  induced  magnetizationdynamics. Electric field excitation of exchange magnons, with no Joule heating, offers a good opportunity fordeveloping nanoscale magnonic devices and exploring various nonlinear dynamics in nanomagnetic systems.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{PhysRevB.105.174415,

title = {Precessional dynamics of geometrically scaled magnetostatic spin waves in two-dimensional magnonic fractals},

author = {J Zhou and Mateusz Zelent and Z Luo and V Scagnoli and Maciej Krawczyk and L J Heyderman and S Saha},

doi = {https://doi.org/10.1103/PhysRevB.105.174415},

year  = {2022},

date = {2022-05-13},

urldate = {2022-05-13},

journal = {Phys. Rev. B },

volume = {105},

number = {174415},

issue = {17},

abstract = {The control of spin waves in periodic magnetic structures has facilitated the realization of many functional magnonic devices, such as band stop filters and magnonic transistors, where the geometry of the crystal structure plays an important role. Here, we report on the magnetostatic mode formation in an artificial magnetic structure, going beyond the crystal geometry to a fractal structure, where the mode formation is related to the geometric scaling of the fractal structure. Specifically, the precessional dynamics was measured in samples with structures going from simple geometric structures toward a Sierpinski carpet and a Sierpinski triangle. The experimentally observed evolution of the precessional motion could be linked to the progression in the geometric structures that results in a modification of the demagnetizing field. Furthermore, we have found sets of modes at the ferromagnetic resonance frequency that form a scaled spatial distribution following the geometric scaling. Based on this, we have determined the two conditions for such mode formation to occur. One condition is that the associated magnetic boundaries must scale accordingly, and the other condition is that the region where the mode occurs must not coincide with the regions for the edge modes. This established relationship between the fractal geometry and the mode formation in magnetic fractals provides guiding principles for their use in magnonics applications.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{gruszecki2022inelastic,

title = {Inelastic Spin-Wave Beam Scattering by Edge-Localized Spin Waves in a Ferromagnetic Thin Film},

author = {Paweł Gruszecki and K Y Guslienko and I L Lyubchanskii and Maciej Krawczyk},

url = {https://link.aps.org/doi/10.1103/PhysRevApplied.17.044038},

doi = {10.1103/PhysRevApplied.17.044038},

year  = {2022},

date = {2022-04-20},

urldate = {2022-04-20},

journal = {Phys. Rev. Appl.},

volume = {17},

number = {15},

issue = {4},

pages = {044038},

abstract = {Spin waves are promising chargeless information carriers for the future, energetically efficient beyond

CMOS systems. Among many advantages are the ease of achieving nonlinearity, the variety of possible interactions, and excitation types. Although the rapidly developing magnonic research has already

yielded impressive realizations, multimode nonlinear effects, particularly with propagating waves and their

nanoscale realizations, are still an open research problem. We theoretically study the dynamic interactions

of spin waves confined to the edge of a thin ferromagnetic film with the spin-wave beam incident at this

edge. We find inelastically scattered spin-wave beams at frequencies increased and decreased by the frequency of the edge spin-wave relative to the specularly reflected beam. We observe a strong dependence

of the angular shift of the inelastic scattered spin-wave beam on the edge-mode frequency, which allows

us to propose a magnonic demultiplexing of the signal encoded in spin waves propagating along the edge.

Since dynamic magnetostatic interactions, which are ubiquitous in the spin-wave dynamics, are decisive

in this process, this indicates the possibility of implementing the presented effects in other configurations

and their use in magnonic systems.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Dhiman2022DMI,

title = {Magnetization statics and dynamics in (Ir/Co/Pt)6 multilayers with Dzyaloshinskii–Moriya interaction},

author = {A K Dhiman and R Gieniusz and Paweł Gruszecki and J Kisielewski and M Matczak and Z Kurant and I Sveklo and U Guzowska and M Tekielak and F Stobiecki and A Maziewski

},

doi = {https://doi.org/10.1063/9.0000339},

year  = {2022},

date = {2022-04-04},

urldate = {2022-04-04},

journal = {AIP Advances},

volume = {12},

number = {4},

pages = {045007},

abstract = {Magnetic multilayers of (Ir/Co/Pt)6 with interfacial Dzyaloshinskii-Moriya interaction (IDMI) were deposited by magnetron sputtering with Co thickness d=1.8 nm. Exploiting magneto-optical Kerr effect in longitudinal mode microscopy, magnetic force microscopy, and vibrating sample magnetometry, the magnetic field-driven evolution of domain structures and magnetization hysteresis loops have been studied. The existence of weak stripe domains structure was deduced – tens micrometers size domains with in-plane “core” magnetization modulated by hundred of nanometers domains with out-of-plane magnetization. Micromagnetic simulations interpreted such magnetization distribution. Quantitative evaluation of IDMI was carried out using Brillouin light scattering (BLS) spectroscopy as the difference between Stokes and anti-Stokes peak frequencies Δf. Due to the additive nature of IDMI, the asymmetric combination of Ir and Pt covers led to large values of effective IDMI energy density Deff. It was found that Stokes and anti-Stokes frequencies as well as Δf, measured as a function of in-plane applied magnetic field, show hysteresis. These results are explained under the consideration of the influence of IDMI on the dynamics of the in-plane magnetized “core” with weak stripe domains},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Serebryannikov_Transmissive_terahertz_metasurfaces,

title = {Transmissive terahertz metasurfaces with vanadium dioxide split-rings and grids for switchable asymmetric polarization manipulation},

author = {Andriy E Serebryannikov and A Lakhtakia and G Vandenbosch and E Ozbay },

doi = {https://doi.org/10.1038/s41598-022-07265-6},

year  = {2022},

date = {2022-03-03},

journal = {Scientific Reports volume },

volume = {12},

pages = {3518 },

abstract = {Metasurfaces containing arrays of thermally tunable metal-free (double-)split-ring meta-atoms and metal-free grids made of vanadium dioxide (VO2), a phase-change material can deliver switching between (1) polarization manipulation in transmission mode as well as related asymmetric transmission and (2) other functionalities in the terahertz regime, especially when operation in the transmission mode is needed to be conserved for both phases of VO2. As the meta-atom arrays function as arrays of metallic subwavelength resonators for the metallic phase of VO2, but as transmissive phase screens for the insulator phase of VO2, numerical simulations of double- and triple-array metasurfaces strongly indicate extreme scenarios of functionality switching also when the resulting structure comprises only VO2 meta-atoms and VO2 grids. More switching scenarios are achievable when only one meta-atom array or one grid is made of VO2 components. They are enabled by the efficient coupling of the geometrically identical resonator arrays/grids that are made of the materials that strongly differ in terms of conductivity, i.e. Cu and VO2 in the metallic phase.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{chumak2022roadmap,

title = {Advances in Magnetics Roadmap on Spin-Wave Computing},

author = {A Chumak and P Kabos and M Wu and C Abert and C Adelmann and A O Adeyeye and J Åkerman and F G Aliev and A Anane and A Awad and C H Back and A Barman and G E W Bauer and M Becherer and E N Beginin and V A S V Bittencourt and Y M Blanter and P Bortolotti and I Boventer and D A Bozhko and S A Bunyaev and J J Carmiggelt and R R Cheenikundil and F Ciubotaru and S Cotofana and G Csaba and O V Dobrovolskiy and C Dubs and M Elyasi and K G Fripp and H Fulara and I A Golovchanskiy and C Gonzalez-Ballestero and Piotr Graczyk and D Grundler and Paweł Gruszecki and G Gubbiotti and K Y Guslienko and A Haldar and S Hamdioui and R Hertel and B Hillebrands and T Hioki and A Houshang and C M Hu and H Huebl and M Huth and E Iacocca and M B Jungfleisch and G N Kakazei and A Khitun and R Khymyn and T Kikkawa and M Kläui and O Klein and Jarosław W Kłos and S Knauer and S Koraltan and M Kostylev and Maciej Krawczyk and I N Krivorotov and V V Kruglyak and D Lachance-Quirion and S Ladak and R Lebrun and Y Li and M Lindner and R Macêdo and S Mayr and G A Melkov and Szymon Mieszczak and Y Nakamura and H T Nembach and A A Nikitin and S A Nikitov and V Novosad and J A Otálora and Y Otani and A Papp and B Pigeau and P Pirro and W Porod and F Porrati and H Qin and Bivas Rana and T Reimann and F Riente and O Romero-Isart and A Ross and A V Sadovnikov and A R Safin and E Saitoh and G Schmidt and H Schultheiss and K Schultheiss and A A Serga and S Sharma and J M Shaw and D Suess and O Surzhenko and Krzysztof Szulc and T Taniguchi and M Urbánek and K Usami and A B Ustinov and T van der Sar and S van Dijken and V I Vasyuchka and R Verba and S Viola Kusminskiy and Q Wang and M Weides and M Weiler and S Wintz and S P Wolski and X Zhang},

doi = {10.1109/TMAG.2022.3149664},

year  = {2022},

date = {2022-02-07},

urldate = {2022-02-07},

journal = {IEEE Transactions on Magnetics},

volume = {58},

number = {6},

issue = {6},

pages = {1-72},

abstract = {Magnonics addresses the physical properties of spin waves and utilizes them for data processing. Scalability down to atomic dimensions, operation in the GHz-to-THz frequency range, utilization of nonlinear and nonreciprocal phenomena, and compatibility with CMOS are just a few of many advantages offered by magnons. Although magnonics is still primarily positioned in the academic domain, the scientific and technological challenges of the field are being extensively investigated, and many proof-of-concept prototypes have already been realized in laboratories. This roadmap is a product of the collective work of many authors, which covers versatile spin-wave computing approaches, conceptual building blocks, and underlying physical phenomena. In particular, the roadmap discusses the computation operations with the Boolean digital data, unconventional approaches, such as neuromorphic computing, and the progress toward magnon-based quantum computing. This article is organized as a collection of sub-sections grouped into seven large thematic sections. Each sub-section is prepared by one or a group of authors and concludes with a brief description of current challenges and the outlook of further development for each research direction.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Sobucki_2022_GTI,

title = {Control of the Phase of Reflected Spin Waves From Magnonic Gires–Tournois Interferometer of Subwavelength Width},

author = {Krzysztof Sobucki and Paweł Gruszecki and Justyna Rychły and Maciej Krawczyk},

doi = {10.1109/TMAG.2021.3088298},

isbn = {0018-9464},

year  = {2022},

date = {2022-02-01},

urldate = {2022-02-01},

journal = {IEEE Transactions on Magnetics},

volume = {58},

pages = {1-5},

abstract = {The phase is one of the fundamental properties of a wave that allows to control interference effects and can be used to efficiently encode information. We examine numerically a magnonic resonator of the Gires–Tournois interferometer type, which enables the control of the phase of spin waves (SWs) reflected from the edge of the ferromagnetic film. The considered interferometer consists of a Py thin film and a thin, narrow Py stripe placed above its edge, both coupled magnetostatically. We show that the resonances and the phase of the reflected SWs are sensitive for a variation of the geometrical parameters of this bi-layered part of the system. The high sensitivity to film, stripe, and non-magnetic spacer thicknesses offers a prospect for developing magnonic metasurfaces and sensors.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Dadoenkova:22,

title = {Goos-Hanchen shift at Brillouin light scattering by a magnetostatic wave in the Damon-Eshbach configuration [Invited]},

author = {Y S Dadoenkova and Maciej Krawczyk and I L Lyubchanski},

doi = {https://doi.org/10.1364/OME.447984},

year  = {2022},

date = {2022-02-01},

journal = {Optical Materials Express},

volume = {12},

pages = {717--726},

abstract = {The lateral shift of an optical beam undergoing Brillouin light scattering by a spin wave propagating along the interface between magnetic and dielectric media (Damon-Eshbach configuration) in the total internal reflection geometry is studied theoretically. Linear and quadratic magneto-optic terms in polarization are taken into account. It is shown that the lateral shift depends on the polarization (s- or p-) state of the scattered electromagnetic wave as well as on the frequency of the spin wave.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{TRZASKOWSKA2022169049,

title = {The studies on phonons and magnons in [CoFeB/Au]N multilayers of different number of repetitions},

author = {Aleksandra Trzaskowska and Piotr Graczyk and Nandan Babu KP and Miłosz Zdunek and H Głowiński and Jarosław W Kłos and Sławomir Mielcarek},

url = {https://www.sciencedirect.com/science/article/pii/S0304885322000300},

doi = {https://doi.org/10.1016/j.jmmm.2022.169049},

issn = {0304-8853},

year  = {2022},

date = {2022-01-13},

urldate = {2022-01-13},

journal = {Journal of Magnetism and Magnetic Materials},

volume = {549},

pages = {169049},

abstract = {We investigated the interaction between spin waves and surface acoustic waves in the [CoFeB/Au]N multilayer deposited on the silicon substrate by Brillion light scattering spectroscopy. We showed that this kind of coupling manifested as an anticrossing in magnetoelastic dispersion relation, can be modified by changing the number of repetitions within the multilayer. The observed modification is attributed mostly to the change in the strength of dipolar interactions which alter the dispersion branch of spin wave fundamental mode and shifts the anticrossing towards larger wave vectors where the magnetoelastic coupling is stronger. The studied range of the wave vector was varied between 0.6·105 cm−1 and 2.2·105 cm−1 while the frequency range of investigations was between 3 and 20 GHz.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{gol_2022_talbot,

title = {Self-imaging of spin waves in thin, multimodeferromagnetic waveguides},

author = {Mateusz Gołębiewski and Paweł Gruszecki and Maciej Krawczyk

},

doi = {10.1109/TMAG.2022.3140280},

year  = {2022},

date = {2022-01-04},

urldate = {2022-01-01},

journal = {IEEE Transactions on Magnetics},

volume = {58},

number = {8},

issue = {8},

pages = {1-5},

abstract = {Self-imaging of waves is an intriguing andspectacular effect. The phenomenon was first observedfor light in 1836 by Henry Fox Talbot and to this dayis the subject of research in many areas of physics,for various types of waves and in terms of differentapplications. This paper is a Talbot-effect study for spinwaves in systems composed of a thin, ferromagneticwaveguide with a series of single-mode sources of spinwaves flowing into it. The proposed systems are studiedwith the use of micromagnetic simulations, and the spinwave self-imaging dependencies on many parameters areexamined. We formulated conditions required for theformation of self-images and suitable for experimentalrealization. The results of the research form the basis forthe further development of self-imaging-based magnonicdevices.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{KUZMA2022168685,

title = {Effects of shape on magnetization switching in systems of magnetic elongated nanoparticles},

author = {D Kuźma and Ł Laskowski and Jarosław W Kłos and P Zieliński},

url = {https://www.sciencedirect.com/science/article/pii/S0304885321009215},

doi = {https://doi.org/10.1016/j.jmmm.2021.168685},

isbn = {0304-8853},

year  = {2022},

date = {2022-01-01},

urldate = {2021-10-23},

journal = {Journal of Magnetism and Magnetic Materials},

volume = {545},

pages = {168685},

abstract = {The equilibrium magnetization of flat elongated magnetic nanoparticles of different shapes has been determined for a range of the static magnetic fields applied parallel to their long/easy axes. The behaviour of single particles has been compared with that of equidistant chains composed of the same particles. The shapes sharpened at the ends, i.e. elongated diamonds and two-sided swords, switch with minimal inhomogeneities of magnetization and with well rectangular hystereses. This may be useful in designing of binary memory devices. The narrowest hysteresis has been found for hourglass shapes, where the switching is preceded with inhomogeneities of magnetization so the hystereses are rounded. The shapes endowed with broadened heads, such as dumbbells and bones, show vortex-like inhomogeneities, marked with an interesting interplay of helicities, which result in a multi-stage switching with relatively large coercive fields.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Tartakovskaya2021,

title = {Engineering spin wave spectra in thick Ni80Fe20 rings by using competition between exchange and dipolar fields},

author = {X Zhou and Elena Tartakovskaya and G N Kakazei and A O Adeyeye},

url = {https://link.aps.org/doi/10.1103/PhysRevB.104.214402},

doi = {10.1103/PhysRevB.104.214402},

year  = {2021},

date = {2021-12-03},

urldate = {2021-12-03},

journal = {Phys. Rev. B},

volume = {104},

number = {21},

pages = {214402},

abstract = {Control of the spin wave dynamics in nanomagnetic elements is very important for the realization of a broad range of novel magnonic devices. Here we study experimentally the spin wave resonance in thick ferromagnetic rings (100 nm) using perpendicular ferromagnetic resonance spectroscopy. Different from what was observed for the continuous film of the same thickness, or from rings with similar lateral dimensions but with lower thicknesses, the spectra of thick patterned rings show a nonmonotonic dependence of the mode intensity on the resonance field for a fixed frequency. To explain this effect, the theoretical approach by considering the dependence of the mode profiles on both the radial and axial coordinates was developed. It was demonstrated that such unusual behavior is a result of the competition between exchange and dipolar fields acting at the spin excitations in the structure under study. The calculations are in a good agreement with the experimental results.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Rana2021b,

title = {Applications of nanomagnets as dynamical systems: II},

author = {Bivas Rana and A K Mondal and S Bandyopadhyay and A Barman},

url = {https://doi.org/10.1088/1361-6528/ac2f59},

doi = {10.1088/1361-6528/ac2f59},

year  = {2021},

date = {2021-11-30},

journal = {Nanotechnology},

volume = {33},

number = {8},

pages = {082002},

abstract = {In Part I of this topical review, we discussed dynamical phenomena in nanomagnets, focusing primarily on magnetization reversal with an eye to digital applications. In this part, we address mostly wave-like phenomena in nanomagnets, with emphasis on spin waves in myriad nanomagnetic systems and methods of controlling magnetization dynamics in nanomagnet arrays which may have analog applications. We conclude with a discussion of some interesting spintronic phenomena that undergird the rich physics exhibited by nanomagnet assemblies.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{kiphart_investigations_2021,

title = {Investigations of proximity-induced superconductivity in the topological insulator Bi2Te3 by microRaman spectroscopy},

author = {D Kiphart and Y Harkavyi and K Balin and J Szade and Bogusław Mróz and P Kuświk and S Jurga and M Wiesner},

url = {https://www.nature.com/articles/s41598-021-02475-w},

doi = {10.1038/s41598-021-02475-w},

issn = {2045-2322},

year  = {2021},

date = {2021-11-26},

journal = {Scientific Reports},

volume = {11},

number = {1},

pages = {22980},

abstract = {We used the topological insulator (TI) Bi2Te3 and a high-temperature superconductor (HTSC) hybrid device for investigations of proximity-induced superconductivity (PS) in the TI. Application of the superconductor YBa2Cu3O7-δ (YBCO) enabled us to access higher temperature and energy scales for this phenomenon. The HTSC in the hybrid device exhibits emergence of a pseudogap state for T textgreater Tc that converts into a superconducting state with a reduced gap for T textless Tc. The conversion process has been reflected in Raman spectra collected from the TI. Complementary charge transport experiments revealed emergence of the proximity-induced superconducting gap in the TI and the reduced superconducting gap in the HTSC, but no signature of the pseudogap. This allowed us to conclude that Raman spectroscopy reveals formation of the pseudogap state but cannot distinguish the proximity-induced superconducting state in the TI from the superconducting state in the HTSC characterised by the reduced gap. Results of our experiments have shown that Raman spectroscopy is a complementary technique to classic charge transport experiments and is a powerful tool for investigation of the proximity-induced superconductivity in the Bi2Te3.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Rana2021a,

title = {Applications of nanomagnets as dynamical systems: I},

author = {S Bandyopadhyay and A K Mondal and Bivas Rana},

doi = {https://doi.org/10.1088/1361-6528/ac2e75},

year  = {2021},

date = {2021-11-19},

urldate = {2021-11-19},

journal = {Nanotechnology},

volume = {33},

number = {6},

abstract = {When magnets are fashioned into nanoscale elements, they exhibit a wide variety of phenomena replete with rich physics and the lure of tantalizing applications. In this topical review, we discuss some of these phenomena, especially those that have come to light recently, and highlight their potential applications. We emphasize what drives a phenomenon, what undergirds the dynamics of the system that exhibits the phenomenon, how the dynamics can be manipulated, and what specific features can be harnessed for technological advances. For the sake of balance, we point out both advantages and shortcomings of nanomagnet based devices and systems predicated on the phenomena we discuss. Where possible, we chart out paths for future investigations that can shed new light on an intriguing phenomenon and/or facilitate both traditional and non-traditional applications.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{tylczynski_collection_2019,

title = {A collection of 505 papers on false or unconfirmed ferroelectric properties in single crystals, ceramics and polymers},

author = {Zbigniew Tylczyński},

url = {https://journal.hep.com.cn/fop/EN/10.1007/s11467-019-0912-5},

doi = {10.1007/s11467-019-0912-5},

issn = {2095-0462},

year  = {2021},

date = {2021-11-19},

journal = {Frontiers of Physics},

volume = {14},

number = {6},

pages = {63301},

abstract = {This collection presents 505 papers on ferroelectricity in single crystals, ceramics and polymers in which pointed or elliptical hysteresis loops would testify to their ferroelectric properties. In some papers, the authors ensure that ferroelectricity can occur even in materials that do not have a polar axis of symmetry.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{PhysRevApplied.16.054033,

title = {Spin-Wave Dispersion Measurement by Variable-Gap Propagating Spin-Wave Spectroscopy},

author = {Marek Vanatka and Krzysztof Szulc and Ondrej Wojewoda and Carsten Dubs and A Chumak and Maciej Krawczyk and Oleksandr V Dobrovolskiy and Jarosław W Kłos and Michal Urbánek},

url = {https://link.aps.org/doi/10.1103/PhysRevApplied.16.054033},

doi = {10.1103/PhysRevApplied.16.054033},

year  = {2021},

date = {2021-11-17},

urldate = {2021-11-17},

journal = {Phys. Rev. Applied},

volume = {16},

pages = {054033},

publisher = {American Physical Society},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Mruczkiewicz2021,

title = {The 2021 roadmap for noncollinear magnonics},

author = {Paweł Gruszecki and Michał Mruczkiewicz},

doi = {https://doi.org/10.1016/bs.ssp.2021.09.001},

issn = {0081-1947},

year  = {2021},

date = {2021-10-26},

urldate = {2021-10-26},

journal = {Solid State Physics},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nano11102627,

title = {Skyrmion Formation in Nanodisks Using Magnetic Force Microscopy Tip},

author = {Mateusz Zelent and Iu. V Vetrova and J Šoltýs and X Li and Y Zhou and V A Gubanov and A V Sadovnikov and T Šcepka and J Dérer and R Stoklas and V Cambel and Michał Mruczkiewicz},

url = {https://www.mdpi.com/2079-4991/11/10/2627},

doi = {10.3390/nano11102627},

year  = {2021},

date = {2021-10-06},

journal = {Nanomaterials},

volume = {11},

number = {10},

abstract = {We demonstrated numerically the skyrmion formation in ultrathin nanodisks using a magnetic force microscopy tip. We found that the local magnetic field generated by the magnetic tip significantly affects the magnetization state of the nanodisks and leads to the formation of skyrmions. Experimentally, we confirmed the influence of the local field on the magnetization states of the disks. Micromagnetic simulations explain the evolution of the magnetic state during magnetic force microscopy scanning and confirm the possibility of skyrmion formation. The formation of the horseshoe magnetic domain is a key transition from random labyrinth domain states into the skyrmion state. We showed that the formation of skyrmions by the magnetic probe is a reliable and repetitive procedure. Our findings provide a simple solution for skyrmion formation in nanodisks.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Barman_2021,

title = {The 2021 Magnonics Roadmap},

author = {A Barman and G Gubbiotti and S Ladak and A O Adeyeye and Maciej Krawczyk and J Gräfe and C Adelmann and S Cotofana and A Naeemi and V I Vasyuchka and B Hillebrands and S A Nikitov and H Yu and D Grundler and A V Sadovnikov and A A Grachev and S E Sheshukova and J-Y Duquesne and M Marangolo and G Csaba and W Porod and V E Demidov and S Urazhdin and S O Demokritov and E Albisetti and D Petti and R Bertacco and H Schultheiss and V V Kruglyak and V D Poimanov and S Sahoo and J Sinha and H Yang and M Münzenberg and T Moriyama and S Mizukami and P Landeros and R A Gallardo and G Carlotti and J-V Kim and R L Stamps and R E Camley and Bivas Rana and Y Otani and W Yu and T Yu and G E W Bauer and C Back and G S Uhrig and O V Dobrovolskiy and B Budinska and H Qin and S Dijken and A Chumak and A Khitun and D E Nikonov and I A Young and B W Zingsem and M Winklhofer},

url = {https://doi.org/10.1088/1361-648x/abec1a},

doi = {10.1088/1361-648x/abec1a},

year  = {2021},

date = {2021-08-18},

urldate = {2021-08-18},

journal = {Journal of Physics: Condensed Matter},

volume = {33},

number = {41},

pages = {413001},

abstract = {Magnonics is a budding research field in nanomagnetism and nanoscience that addresses the use of spin waves (magnons) to transmit, store, and process information. The rapid advancements of this field during last one decade in terms of upsurge in research papers, review articles, citations, proposals of devices as well as introduction of new sub-topics prompted us to present the first roadmap on magnonics. This is a collection of 22 sections written by leading experts in this field who review and discuss the current status besides presenting their vision of future perspectives. Today, the principal challenges in applied magnonics are the excitation of sub-100 nm wavelength magnons, their manipulation on the nanoscale and the creation of sub-micrometre devices using low-Gilbert damping magnetic materials and its interconnections to standard electronics. To this end, magnonics offers lower energy consumption, easier integrability and compatibility with CMOS structure, reprogrammability, shorter wavelength, smaller device features, anisotropic properties, negative group velocity, non-reciprocity and efficient tunability by various external stimuli to name a few. Hence, despite being a young research field, magnonics has come a long way since its early inception. This roadmap asserts a milestone for future emerging research directions in magnonics, and hopefully, it will inspire a series of exciting new articles on the same topic in the coming years.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Ercaglar:21,

title = {Multifunctional tunable gradient metasurfaces for terahertz beam splitting and light absorption},

author = {V Erçağlar and H Hajian and Andriy E Serebryannikov and E Ozbay},

url = {http://ol.osa.org/abstract.cfm?URI=ol-46-16-3953},

doi = {10.1364/OL.435197},

year  = {2021},

date = {2021-08-09},

urldate = {2021-08-09},

journal = {Opt. Lett.},

volume = {46},

number = {16},

pages = {3953--3956},

abstract = {Obtaining functional devices with tunable features is beneficial to advance terahertz (THz) science and technology. Here, we propose multifunctional gradient metasurfaces that are composed of a periodic array of binary Si microcylinders integrated with VO2 and graphene. The metasurfaces act as transmittive (reflective) beamsplitters for the dielectric (metallic) phase of VO2 with a switchable characteristic. Moreover, by integrating the metasurfaces with graphene and modifying its chemical potential, one can tune the intensity of the split beam as well as obtain nearly perfect resonant absorptions. Consequently, the proposed metasurfaces can find potential applications in THz interferometers, multiplexers, and light absorbers.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{graczyk_nonresonant_2021,

title = {Nonresonant amplification of spin waves through interface magnetoelectric effect and spin-transfer torque},

author = {Piotr Graczyk and Maciej Krawczyk},

url = {https://www.nature.com/articles/s41598-021-95267-1},

doi = {10.1038/s41598-021-95267-1},

year  = {2021},

date = {2021-08-03},

journal = {Scientific Reports},

volume = {11},

number = {1},

pages = {15692},

abstract = {We present a new mechanism for manipulation of the spin-wave amplitude through the use of the dynamic charge-mediated magnetoelectric effect in ultrathin multilayers composed of dielectric thin-film capacitors separated by a ferromagnetic bilayer. Propagating spin waves can be amplified and attenuated with rising and decreasing slopes of the oscillating voltage, respectively, locally applied to the sample. The way the spin accumulation is generated makes the interaction of the spin-transfer torque with the magnetization dynamics mode-selective and restricted to some range of spin-wave frequencies, which is contrary to known types of the spin-transfer torque effects. The interfacial nature of spin-dependent screening allows to reduce the thickness of the fixed magnetization layer to a few nanometers, thus the proposed effect significantly contributes toward realization of the magnonic devices and also miniaturization of the spintronic devices.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{TRZASKOWSKA2021106526,

title = {Dispersion of the surface phonons in semiconductor/topological insulator Si/Bi2Te3 heterostructure studied by high resolution Brillouin spectroscopy},

author = {Aleksandra Trzaskowska and Sławomir Mielcarek and M Wiesner and F Lombardi and Bogusław Mróz},

url = {https://www.sciencedirect.com/science/article/pii/S0041624X21001554},

doi = {https://doi.org/10.1016/j.ultras.2021.106526},

year  = {2021},

date = {2021-07-21},

urldate = {2021-07-21},

journal = {Ultrasonics},

volume = {117},

pages = {106526},

abstract = {The dynamics and dispersion of surface phonons in heterostructure semiconductor/ topological insulator Si/Bi2Te3 was investigated using high resolution Brillouin light scattering method in the GHz frequency range. Both Rayleigh and Sezawa surface acoustic waves have been observed for wave vectors ranging from 0.006 to 0.023 nm−1. Anomaly in dispersion relations ω(q) for both surface waves were detected for the wave vector q = 0.016 nm−1. The finite element method (FEM) was used to simulate the observed shapes of ω(q) and to find the deformation profiles of surface acoustic waves. We attribute the observed changes to the coupling between low energy electrons and surface phonons. The coupling between helical Dirac states and surface phonons is discussed in the frame of accessible theoretical models.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{PhysRevLett.127.037201,

title = {Quantifying and Controlling Entanglement in the Quantum Magnet Cs2CoCl4},

author = {P Laurell and A Scheie and C J Mukherjee and M M Koza and M Enderle and Zbigniew Tylczyński and S Okamoto and R Coldea and A D Tennant and G Alvarez},

url = {https://link.aps.org/doi/10.1103/PhysRevLett.127.037201},

doi = {10.1103/PhysRevLett.127.037201},

year  = {2021},

date = {2021-07-13},

journal = {Phys. Rev. Lett.},

volume = {127},

pages = {037201},

abstract = {The lack of methods to experimentally detect and quantify entanglement in quantum matter impedes our ability to identify materials hosting highly entangled phases, such as quantum spin liquids. We thus investigate the feasibility of using inelastic neutron scattering (INS) to implement a model-independent measurement protocol for entanglement based on three entanglement witnesses: one-tangle, two-tangle, and quantum Fisher information (QFI). We perform high-resolution INS measurements on Cs2CoCl4, a close realization of the S=1/2 transverse-field XXZ spin chain, where we can control entanglement using the magnetic field, and compare with density-matrix renormalization group calculations for validation. The three witnesses allow us to infer entanglement properties and make deductions about the quantum state in the material. We find QFI to be a particularly robust experimental probe of entanglement, whereas the one and two-tangles require more careful analysis. Our results lay the foundation for a general entanglement detection protocol for quantum spin systems.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Gundogdu:21,

title = {Evidence of asymmetric beaming in a piecewise-linear propagation channel},

author = {T F Gundogdu and M Gokkavas and Andriy E Serebryannikov and E Ozbay},

url = {https://opg.optica.org/ol/abstract.cfm?URI=ol-46-12-2928},

doi = {10.1364/OL.420297},

year  = {2021},

date = {2021-06-14},

journal = {Opt. Lett.},

volume = {46},

number = {12},

pages = {2928--2931},

abstract = {Asymmetric beaming in a piecewise-linear propagation channel is demonstrated for a single photonic-crystal prism at Gaussian-beam illumination. The used hybrid refraction--diffraction mechanism exploits oblique incidence, the first-negative-order deflection at the longer interface, and asymmetry in coupling at the exit interfaces and does not need blocking of transmission by dispersion in the backward illumination case. The Floquet--Bloch mode with left-handed behavior and nearly circular equifrequency dispersion contours is utilized. The outgoing waves may have significantly different spatial distributions for the forward and backward illumination cases, yielding asymmetry in the beaming regime.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{doi:10.1063/5.0045142,

title = {Phase resolved observation of spin wave modes in antidot lattices},

author = {F Groß and Mateusz Zelent and A Gangwar and Sławomir Mamica and Paweł Gruszecki and M Werner and G Schütz and M Weigand and E J Goering and C H Back and Maciej Krawczyk and J Gräfe},

url = {https://doi.org/10.1063/5.0045142},

doi = {10.1063/5.0045142},

year  = {2021},

date = {2021-06-10},

journal = {Appl. Phys. Lett.},

volume = {118},

number = {23},

pages = {232403},

abstract = {Antidot lattices have proven to be a powerful tool for spin wave band structure manipulation. Utilizing time-resolved scanning transmission 

x-ray microscopy, we are able to experimentally image edge-localized spin wave modes in an antidot lattice with a lateral confinement down to <80nm x 130 nm. At higher frequencies, spin wave dragonfly patterns formed by the demagnetizing structures of the antidot lattice are excited. Evaluating their relative phase with respect to the propagating mode within the antidot channel reveals that the dragonfly modes are not directly excited by the antenna but need the propagating mode as an energy mediator. Furthermore, micromagnetic simulations reveal that additional dispersion branches exist for a tilted external field geometry. These branches correspond to asymmetric spin wave modes that cannot be excited in a non-tilted field geometry due to the symmetry restriction. In addition to the band having a negative slope, these asymmetric modes also cause an unexpected transformation of the band structure, slightly reaching into the otherwise empty bandgap between the low frequency edge modes and the fundamental mode. The presented phase resolved investigation of spin waves is a crucial step for spin wave manipulation in magnonic crystals.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{doi:10.1063/5.0045835,

title = {Investigation of self-nucleated skyrmion states in the ferromagnetic/nonmagnetic multilayer dot},

author = {Iu. V Vetrova and Mateusz Zelent and J Šoltýs and V A Gubanov and A V Sadovnikov and T Šcepka and J Dérer and R Stoklas and V Cambel and Michał Mruczkiewicz},

doi = {10.1063/5.0045835},

year  = {2021},

date = {2021-05-28},

journal = {Appl. Phys. Lett.},

volume = {118},

number = {21},

pages = {212409},

abstract = {Understanding the stability of magnetic textures in multilayer patterned dots would constitute a significant step toward skyrmion-based applications. Here, we report the observation of skyrmions in patterned nanodots composed of multilayers. We examine the stabilization of various magnetic states such as single-domain states, skyrmion states, horseshoe-like domain structures, and worm-like domain structures in submicrometer dots (diameters 150–525 nm). Dots are fabricated from Pt/Co/Au multilayer structures that exhibit the interfacial Dzyaloshinskii–Moriya interaction and perpendicular magnetic anisotropy. In particular, we show that a stack of six repetitions of Pt/Co/Au layers suffices to stabilize the skyrmion state inside a dot at room temperature. A micromagnetic simulation determines the regime of skyrmion stability. The results reveal a correlation between the magnetic-force microscopy measurements and the micromagnetic simulation. Furthermore, we explain the development of the magnetic state with increasing dot diameter. We envision that nanopatterning of multilayer magnetic films could serve as a versatile way of creating magnetic skyrmion states.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{000231402,

title = {Trabecular bone remodelling in the femur of C57BL/6J mice treated with diclofenac in combination with treadmill exercise},

author = {T Lehmann and M Wojtków and E Pruszynska-Oszmałek and P Kołodziejski and C Pezowicz and Aleksandra Trzaskowska and Sławomir Mielcarek and M Szybowicz and A B Nowicka and M Nowicki and E Misterska and E Iwańczyk-Skalska and P Jagodziński and M Głowacki},

url = {http://www.actabio.pwr.wroc.pl/Vol23No3/41.pdf},

year  = {2021},

date = {2021-05-13},

journal = {Acta of Bioengineering and Biomechanics},

volume = {23},

number = {3},

pages = {1-17},

abstract = {Analgesic treatment with diclofenac deteriorates bone structure and decreases biomechanical properties. This bone

loss has been though to be reversed by training. The impact of exercise on bone treated with diclofenac (DF) has reminded elusive.

In the present study, we assayed the combined impact of exercises and DF on mouse femur. Methods: The femur samples we

obtained from 30 days treated C57BL/6J female mice. The training group ran on a horizontal treadmill at 12 m/min by 30 min

a day (5% grade/slope). The group of ten mice treated with DF received the drug subcutaneously every day (5 mg/kg of body

weight/day). The combined group ran on the treadmill and obtained DF. After 30 days, we sacrificed mice and studied their femurs

using microcomputed tomography (μCT), dynamic mechanical analysis (DMA) and nanoindentation. Results: We observed

that treadmill running and DF decreased trabecular bone volume and mineral density. Combined effect of training and DF was not

additive. A significant interaction of both parameters suggested protective effect of training on bone loss provoked by DF. The femur

cortical bone shell remained untouched by the training and treatment. The training and the DF treatment did not alter the storage

modulus E¢ significantly. The unchanged storage modulus would be suggesting on the unaltered bone strength. Conclusions:

We concluded that even relatively short time of training with concomitant DF treatment could be protective on trabecular bone.

Although viscoelastic properties of the entire femur were not modulated, femur trabecular tissue was thinned by treatment with

DF and protected by training.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{doi:10.1063/5.0046001b,

title = {Multifunctional operation of the double-layer ferromagnetic structure coupled by a rectangular nanoresonator},

author = {Pierre Roberjot and Krzysztof Szulc and Jarosław W Kłos and Maciej Krawczyk},

url = {https://doi.org/10.1063/5.0046001},

doi = {10.1063/5.0046001},

year  = {2021},

date = {2021-05-05},

urldate = {2021-05-05},

journal = {Appl. Phys. Lett.},

volume = {118},

number = {18},

pages = {182406},

abstract = {The use of spin waves as a signal carrier requires developing the functional elements allowing for multiplexing and demultiplexing information coded at different wavelengths. For this purpose, we propose a system of thin ferromagnetic layers dynamically coupled by a rectangular ferromagnetic resonator. We show that single and double, clockwise and counterclockwise, circulating modes of the resonator offer a wide possibility of control of propagating waves. Particularly, at frequency related to the double-clockwise circulating spin-wave mode of the resonator, the spin wave excited in one layer is transferred to the second one where it propagates in the backward direction. Interestingly, the wave excited in the second layer propagates in the forward direction only in that layer. This demonstrates add-drop filtering and circulator functionality. Thus, the proposed system can become an important part of future magnonic technology for signal routing.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Osgouei_2021,

title = {Hybrid indium tin oxide-Au metamaterial as a multiband bi-functional light absorber in the visible and near-infrared ranges},

author = {A K Osgouei and H Hajian and Andriy E Serebryannikov and E Ozbay},

url = {https://doi.org/10.1088/1361-6463/abf579},

doi = {10.1088/1361-6463/abf579},

year  = {2021},

date = {2021-04-23},

urldate = {2021-04-23},

journal = {J. Phys. D: Appl. Phys.},

volume = {54},

number = {27},

pages = {275102},

abstract = {Metamaterial nearly perfect light absorbers (MPAs) with dual-narrowband functionality—that absorb light in two narrowband adjacent wavelength regions—have attracted considerable attention due to their intriguing applications, such as sensing, photovoltaic, and thermal emission. Here, we propose a multi-band MPA with two narrowband absorption responses that are centered on the visible and near-infrared (NIR) wavelengths (773 nm and 900 nm, respectively) and a broadband absorptive characteristic in another window in the NIR region (ranging from 1530 nm to 2700 nm with a bandwidth of 1170 nm). The MPA comprises a periodic array of self-aligned hybrid indium tin oxide (ITO)-Au split-ring-resonators that are separated from an optically thick bottom reflector with a SiO2 layer. Based on numerical calculations, which are accompanied with a semi-analytical examination, we find that the dual narrowband and broadband responses are attributed to the hybridization of the optical responses of gold as a plasmonic material with the ones of ITO. Note that ITO acts as a low-loss dielectric in the visible range and a lossy plasmonic material in the NIR region. Moreover, due to the applied symmetry in the unit cell of the metamaterial, the proposed MPA represents polarization insensitive and omnidirectional absorptive features. The proposed metastructure can find potential applications in selective thermophotovoltaic devices, thermal emitters, and sensors.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{PhysRevB.103.134404,

title = {Nonreciprocal spin-wave dynamics in Pt/Co/W/Co/Pt multilayers},

author = {Krzysztof Szulc and S Mendisch and Michał Mruczkiewicz and F Casoli and M Becherer and G Gubbiotti},

url = {https://link.aps.org/doi/10.1103/PhysRevB.103.134404},

doi = {10.1103/PhysRevB.103.134404},

year  = {2021},

date = {2021-04-01},

journal = {Phys. Rev. B},

volume = {103},

pages = {134404},

abstract = {We present a detailed study of the spin-wave dynamics in single Pt/Co/W and double Pt/Co/W/Co/Pt ferromagnetic layer systems. The dispersion of spin waves was measured by wave-vector-resolved Brillouin light scattering spectroscopy while the in-plane and out-of-plane magnetization curves were measured by alternating gradient field magnetometry. The interfacial Dzyaloshinskii-Moriya interaction induced nonreciprocal dispersion relation was demonstrated for both single and double ferromagnetic layers and explicated by numerical simulations and theoretical formulas. The results indicate the crucial role of the order of layers deposition on the magnetic parameters. A significant difference between the perpendicular magnetic anisotropy constant in double ferromagnetic layer systems conduces to the decline of the interlayer interactions and different dispersion relations for the spin-wave modes. Our study provides a significant contribution to the realization of the multifunctional nonreciprocal magnonic devices based on ultrathin ferromagnetic/heavy-metal layer systems.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{sobucki_resonant_2021,

title = {Resonant subwavelength control of the phase of spin waves reflected from a Gires–Tournois interferometer},

author = {Krzysztof Sobucki and Wojciech Śmigaj and Justyna Rychły and Maciej Krawczyk and Paweł Gruszecki},

url = {https://www.nature.com/articles/s41598-021-83307-9},

doi = {10.1038/s41598-021-83307-9},

year  = {2021},

date = {2021-02-24},

urldate = {2021-02-24},

journal = {Sci. Rep.},

volume = {11},

number = {1},

pages = {4428},

abstract = {Subwavelength resonant elements are essential building blocks of metamaterials and metasurfaces, which have revolutionized photonics. Despite similarities between different wave phenomena, other types of interactions can make subwavelength coupling significantly distinct; its investigation in their context is therefore of interest both from the physics and applications perspective. In this work, we demonstrate a fully magnonic Gires–Tournois interferometer based on a subwavelength resonator made of a narrow ferromagnetic stripe lying above the edge of a ferromagnetic film. The bilayer formed by the stripe and the film underneath supports two propagative spin-wave modes, one strongly coupled with spin waves propagating in the rest of the film and another almost completely reflected at the ends of the bilayer. When the Fabry–Perot resonance conditions for this mode are satisfied, the weak coupling between both modes is sufficient to achieve high sensitivity of the phase of waves reflected from the resonator to the stripe width and, more interestingly, also to the stripe-film separation. Such spin-wave phase manipulation capabilities are a prerequisite for the design of spin-wave metasurfaces and may stimulate development of magnonic logic devices and sensors detecting magnetic nanoparticles.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{doi:10.1063/5.0041030,

title = {Local non-linear excitation of sub-100 nm bulk-type spin waves by edge-localized spin waves in magnetic films},

author = {Paweł Gruszecki and I L Lyubchanskii and K Y Guslienko and Maciej Krawczyk},

doi = {10.1063/5.0041030},

year  = {2021},

date = {2021-02-11},

journal = {Appl. Phys. Lett.},

volume = {118},

number = {6},

pages = {062408},

abstract = {The excitation of high-frequency short-wavelength spin waves is a challenge limiting the application of these propagating magnetization disturbances in information processing systems. We propose a method of local excitation of the high-frequency spin waves using the non-linear nature of magnetization dynamics. We demonstrate with numeric simulations that an edge-localized spin wave can be used to excite plane waves propagating obliquely from the film's edge at a doubled frequency and over twice shorter in wavelength. The excitation mechanism is a direct result of the ellipticity of the magnetic moment precession that is related to the edge-mode propagation. As a consequence, the magnetization component tangential to the equilibrium orientation oscillates with doubled temporal and spatial frequencies, which leads to efficient excitation of the plane spin waves. The threshold-less non-linear process of short-wavelength spin-wave excitation proposed in our study is promising for integration with an inductive or point-like spin-torque source of edge spin waves. 

The research leading to these results received funding from the National Science Centre of Poland, Project No. 2019/35/D/ST3/03729. I.L.L. acknowledges support from a COST action under Project No. CA17123 MAGNETOFON. K.Y.G. acknowledges support from IKERBASQUE (the Basque Foundation for Science) and from the Spanish Ministerio de Ciencia, Innovacion y Universidades Grant No. PID2019-108075RB-C33/AEI/10.13039/501100011033. The simulations were partially performed at the Poznan Supercomputing and Networking Center (Grant No. 398).},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{PhysRevLett.126.057201,

title = {Real-Space Observation of Magnon Interaction with Driven Space-Time Crystals},

author = {N Träger and Paweł Gruszecki and F Lisiecki and F Groß and J Förster and M Weigand and H Głowiński and P Kuświk and Janusz Dubowik and G Schütz and Maciej Krawczyk and J Gräfe},

url = {https://doi.org/10.1103/PhysRevLett.126.057201},

doi = {10.1103/PhysRevLett.126.057201},

year  = {2021},

date = {2021-02-03},

journal = {Phys. Rev. Lett.},

volume = {126},

pages = {057201},

abstract = {The concept of space-time crystals (STC), i.e., translational symmetry breaking in time and space, was recently proposed and experimentally demonstrated for quantum systems. Here, we transfer this concept to magnons and experimentally demonstrate a driven STC at room temperature. The STC is realized by strong homogeneous microwave pumping of a micron-sized permalloy (Py) stripe and is directly imaged by scanning transmission x-ray microscopy (STXM). For a fundamental understanding of the formation of the STC, micromagnetic simulations are carefully adapted to model the experimental findings. Beyond the mere generation of a STC, we observe the formation of a magnonic band structure due to back folding of modes at the STC’s Brillouin zone boundaries. We show interactions of magnons with the STC that appear as lattice scattering, which results in the generation of ultrashort spin waves (SW) down to 100-nm wavelengths that cannot be described by classical dispersion relations for linear SW excitation. We expect that room-temperature STCs will be useful to investigate nonlinear wave physics, as they can be easily generated and manipulated to control their spatial and temporal band structures.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{PhysRevB.103.014430,

title = {Competing spin wave emission mechanisms revealed by time-resolved x-ray microscopy},

author = {N Trager and F Lisiecki and R Lawitzki and M Weigand and H Głowiński and G Schütz and G Schmitz and P Kuświk and Maciej Krawczyk and J Gräfe and Paweł Gruszecki},

url = {https://link.aps.org/doi/10.1103/PhysRevB.103.014430},

doi = {10.1103/PhysRevB.103.014430},

year  = {2021},

date = {2021-01-19},

urldate = {2021-01-19},

journal = {Phys. Rev. B},

volume = {103},

pages = {014430},

abstract = {Spin wave emission and propagation in magnonic waveguides represent a highly promising alternative for beyond-CMOS computing. It is therefore all the more important to fully understand the underlying physics of the emission process. Here, we use time-resolved scanning transmission x-ray microscopy to directly image the formation process of the globally excited local emission of spin waves in a permalloy waveguide at the nanoscale. Thereby, we observe spin wave emission from the corner of the waveguide as well as from a local oscillation of a domain-wall-like structure within the waveguide. Additionally, an isofrequency contour analysis is used to fully explain the origin of quasicylindrical spin wave excitation from the corner and its concurrent nonreflection and nonrefraction at the domain interface. This study is complemented by micromagnetic simulations which perfectly fit the experimental findings. Thus, we clarify the fundamental question of the emission mechanisms in magnonic waveguides which lay the basis for future magnonic operations.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{kalantari_osgouei_active_2021,

title = {Active Tuning from Narrowband to Broadband Absorbers Using a Sub-wavelength VO2 Embedded Layer},

author = {A K Osgouei and H Hajian and B Khalichi and Andriy E Serebryannikov and A Ghobadi and E Ozbay},

url = {https://doi.org/10.1007/s11468-020-01370-w},

doi = {10.1007/s11468-020-01370-w},

year  = {2021},

date = {2021-01-18},

urldate = {2021-01-18},

journal = {Plasmonics},

abstract = {Metamaterial perfect absorbers (MPAs) with dynamic thermal tuning features are able to control the absorption performance of the resonances, providing diverse applications spanning from optical switches and filters to modulators. In this paper, we propose an MPA with diverse functionalities enabled by vanadium dioxide (VO2) embedded in a metal-dielectric plasmonic structure. For the initial design purpose, a silicon (Si) nanograting on a silver (Ag) mirror is proposed to have multiple resonant responses in the near infrared (NIR) region. Then, the insertion of a thin VO2 layer at the right position enables the design to act as an on/off switch and resonance tuner. In the insulator phase of VO2, in which the permittivity data of VO2 is similar to that of Si, a double strong resonant behavior is achieved within the NIR region. By increasing the temperature, the state of VO2 transforms from insulator to metallic so that the absorption bands turn into three distinct resonant peaks with close spectral positions. Upon this transformation, a new resonance emerges and the existing resonance features experience blue/red shifts in the spectral domain. The superposition of these peaks makes the overall absorption bandwidth broad. Although Si has a small thermo-optic coefficient, owing to strong light confinement in the ultrasmall gaps, a substantial tuning can be achieved within the Si nanogratings. Therefore, the proposed hybrid design can provide multi-resonance tunable features to cover a broad range and can be a promising strategy for the design of linearly thermal-tunable and broadband MPAs. Owing to the proposed double tuning feature, the resonance wavelengths exhibits great sensitivity to temperature, covering a broad wavelength range$$.$$Overall, the proposed design strategy demonstrates diverse functionalities enabled by the integration of a thin VO2 layer with plasmonic absorbers.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Babu2021,

title = {The Interaction between Surface Acoustic Waves and Spin Waves: The Role of Anisotropy and Spatial Profiles of the Modes},

author = {Nandan Babu KP and Aleksandra Trzaskowska and Piotr Graczyk and Grzegorz Centała and Szymon Mieszczak and Hubert Głowiński and Miłosz Zdunek and Sławomir Mielcarek and Jarosław W Kłos},

url = {https://doi.org/10.1021/acs.nanolett.0c03692},

doi = {10.1021/acs.nanolett.0c03692},

year  = {2021},

date = {2021-01-01},

urldate = {2021-01-01},

journal = {Nano Lett.},

volume = {21},

number = {2},

pages = {946-951},

abstract = {The interaction between different types of wave excitation in hybrid systems is usually anisotropic. Magnetoelastic coupling between surface acoustic waves and spin waves strongly depends on the direction of the external magnetic field. However, in the present study we observe that even if the orientation of the field is supportive for the coupling, the magnetoelastic interaction can be significantly reduced for surface acoustic waves with a particular profile in the direction normal to the surface at distances much smaller than the wavelength. We use Brillouin light scattering for the investigation of thermally excited phonons and magnons in a magnetostrictive CoFeB/Au multilayer deposited on a Si substrate. The experimental data are interpreted on the basis of a linearized model of interaction between surface acoustic waves and spin waves.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{dobrovolskiy2020spin,

title = {Spin-wave spectroscopy of individual ferromagnetic nanodisks},

author = {O V Dobrovolskiy and S A Bunyaev and N R Vovk and D Navas and Paweł Gruszecki and Maciej Krawczyk and R Sachser and M Huth and A Chumak and K Y Guslienko and G N Kakazei },

doi = {10.1039/D0NR07015G },

year  = {2020},

date = {2020-10-06},

urldate = {2020-10-06},

journal = {Nanoscale},

volume = {12},

number = {41},

pages = {21207-21217},

abstract = {The increasing demand for nanoscale magnetic devices requires development of 3D magnetic nanostructures. In this regard, focused electron beam induced deposition (FEBID) is a technique of choice for direct-writing of complex nano-architectures with applications in nanomagnetism, magnon spintronics, and superconducting electronics. However, intrinsic properties of nanomagnets are often poorly known and can hardly be assessed by local optical probe techniques. Here, an original spatially resolved approach is demonstrated for spin-wave spectroscopy of individual circular magnetic elements with sample volumes down to about 10−3 μm3. The key component of the setup is a coplanar waveguide whose microsized central part is placed over a movable substrate with well-separated CoFe-FEBID nanodisks which exhibit standing spin-wave resonances. The circular symmetry of the disks allows for the deduction of the saturation magnetization and the exchange stiffness of the material using an analytical theory. A good correspondence between the results of analytical calculations and micromagnetic simulations is revealed, indicating a validity of the used analytical model going beyond the initial thin-disk approximation used in the theoretical derivation. The presented approach is especially valuable for the characterization of direct-write magnetic elements opening new horizons for 3D nanomagnetism and magnonics.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{trager2020direct,

title = {Direct Imaging of High Frequency Multimode Spin Wave Propagation in CoFe Waveguides using X‐Ray Microscopy beyond 10 GHz},

author = {N Träger and Paweł Gruszecki and F Lisiecki and J Förster and M Weigand and S Wintz and H Stoll and H Głowiński and P Kuświk and Maciej Krawczyk and J Gräfe},

year  = {2020},

date = {2020-09-04},

urldate = {2020-10-06},

journal = {Rapid Research Letters},

volume = {14},

number = {12},

pages = {2000373},

abstract = {Not only in fundamental wave physics but also in technical areas such as radar

and communication systems, high-frequency magnonics is increasingly attracting

attention. Here, time-resolved scanning transmission X-ray microscopy is used to

directly image high-frequency spin wave propagation in cobalt-iron waveguides at

excitation frequencies above 10 GHz. In addition, an excitation technique is

presented, which allows for versatile pump–probe experiments with radio frequency currents up to 30 GHz. With this approach, a global sinusoidal magnetic

field excitation is applied to induce spin waves from the waveguide edges.

Amplitude, relative phase, and k-space information as a function of excitation

frequencies and static external fields are observed, matching the theoretical

predictions for confined waveguide structures. In doing so, the foundation for

high-frequency multimode spin wave excitation and propagation at the nanoscale

is laid, which can be a prospective path in radar and communication systems.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{PhysRevApplied.14.034063,

title = {Spin-wave diode and circulator based on unidirectional coupling},

author = {Krzysztof Szulc and Piotr Graczyk and Michał Mruczkiewicz and G Gubbiotti and Maciej Krawczyk},

url = {https://link.aps.org/doi/10.1103/PhysRevApplied.14.034063},

doi = {10.1103/PhysRevApplied.14.034063},

year  = {2020},

date = {2020-09-01},

journal = {Physical Review Applied},

volume = {14},

pages = {034063},

abstract = {In magnonics, a fast-growing branch of wave physics characterized by low energy consumption, it is highly desirable to create circuit elements useful for wave computing. However, it is crucial to reach the nanoscale so as to be competitive with the electronics, which vastly dominates in computing devices. Here, based on numerical simulations, we demonstrate the functionality of the spin-wave diode and the circulator to steer and manipulate spin waves over a wide range of frequency in the GHz regime. They take advantage of the unidirectional magnetostatic coupling induced by the interfacial Dzyaloshinskii-Moriya interaction, allowing the transfer of the spin wave between thin ferromagnetic layers in only one direction of propagation. Using the multilayered structure consisting of Py and Co in direct contact with heavy metal, we obtain submicrometer-size nonreciprocal devices of high efficiency. Thus, our work contributes to the emerging branch of energy-efficient magnonic logic devices, giving rise to the possibility of application as a signal-processing unit in the digital and analog nanoscaled spin-wave circuits.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{PhysRevApplied.13.054038,

title = {Anomalous pefraction of spin waves as a way to guide signals in curved magnonic multimode waveguides},

author = {Szymon Mieszczak and O Busel and Paweł Gruszecki and A N Kuchko and Jarosław W Kłos and Maciej Krawczyk},

url = {https://link.aps.org/doi/10.1103/PhysRevApplied.13.054038},

doi = {10.1103/PhysRevApplied.13.054038},

year  = {2020},

date = {2020-05-01},

journal = {Physical Review Applied},

volume = {13},

pages = {054038},

abstract = {We present a method for efficient spin-wave guiding within the magnonic nanostructures. Our technique is based on the anomalous refraction in the metamaterial flat slab. The gradual change of the material parameters (saturation magnetization or magnetic anisotropy) across the slab allows tilting the wavefronts of the transmitted spin waves and controlling the refraction. Numerical studies of the spin-wave refraction are preceded by the analytical calculations of the phase shift acquired by the spin wave due to the change of material parameters in a confined area. We demonstrate that our findings can be used to guide the spin waves smoothly in curved waveguides, even through sharp bends, without reflection and scattering between different waveguide’s modes, preserving the phase, the quantity essential for wave computing.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{microscopy,

title = {Demonstration of k-vector selective microscopy for nanoscale mapping of higher order spin wave modes},

author = {N Trager and Paweł Gruszecki and F Lisiecki and F Gross and J Forster and M Weigand and H Głowiński and P Kuświk and Janusz Dubowik and Maciej Krawczyk and J Gräfe},

url = {https://pubs.rsc.org/en/content/articlelanding/2020/nr/d0nr02132f#!divAbstract},

doi = {10.1039/d0nr02132f},

year  = {2020},

date = {2020-01-01},

journal = {Nanoscale},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{lens,

title = {Direct observation of spin-wave focusing by a Fresnel lens},

author = {J Gräfe and Paweł Gruszecki and Mateusz Zelent and M Decker and K Keskinbora and M Noske and P Gawroński and H Stoll and M Weigand and Maciej Krawczyk and C H Back and E J Goering and G Schutz},

url = {https://journals.aps.org/prb/abstract/10.1103/PhysRevB.102.024420},

doi = {10.1103/PhysRevB.102.024420},

year  = {2020},

date = {2020-01-01},

journal = {Physical Review B},

volume = {102},

pages = {024420},

abstract = {Spin waves are discussed as promising information carrier for beyond complementary metal-oxide semiconductor data processing. One major challenge is guiding and steering of spin waves in a uniform film. Here, we explore the use of diffractive optics for these tasks by nanoscale real-space imaging using x-ray microscopy and careful analysis with micromagnetic simulations. We discuss the properties of the focused caustic beams that are generated by a Fresnel-type zone plate and demonstrate control and steering of the focal spot. Thus, we present a steerable and intense nanometer-sized spin-wave source. Potentially, this could be used to selectively illuminate magnonic devices like nano-oscillators.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{edge_1,

title = {Edge localization of spin waves in antidot multilayers with perpendicular magnetic anisotropy},

author = {S Pan and S Mondal and Mateusz Zelent and R Szwierz and S Pal and O Hellwig and Maciej Krawczyk and A Barman},

url = {https://journals.aps.org/prb/abstract/10.1103/PhysRevB.101.014403},

doi = {10.1103/PhysRevB.101.014403},

year  = {2020},

date = {2020-01-01},

journal = {Physical Review B},

volume = {101},

pages = {014403},

abstract = {We study the spin-wave dynamics in nanoscale antidot lattices based on Co/Pd multilayers with perpendicular magnetic anisotropy. Using time-resolved magneto-optical Kerr effect measurements we demonstrate that the variation of the antidot shape introduces significant change in the spin-wave spectra, especially in the lower frequency range. By employing micromagnetic simulations we show that additional peaks observed in the measured spectra are related to narrow shell regions around the antidots, where in-plane domain structures are formed. This is because the magnetic anisotropy in these regions is reduced due to the Ga+ ion irradiation during the focused ion beam milling process of the antidot fabrication. The results point at possibilities for exploitation of localized spin waves in out-of-plane magnetized thin films, which are easily tunable and suitable for magnonic applications.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Yildirim:20,

title = {One-way and near-absolute polarization insensitive near-perfect absorption by using an all-dielectric metasurface},

author = {D U Yildirim and A Ghobadi and M C Soydan and Andriy E Serebryannikov and E Ozbay},

url = {http://ol.osa.org/abstract.cfm?URI=ol-45-7-2010},

doi = {10.1364/OL.387350},

year  = {2020},

date = {2020-01-01},

journal = {Optics Letters},

volume = {45},

number = {7},

pages = {2010--2013},

abstract = {In this Letter, we numerically propose the one-way perfect absorption of near-infrared radiation in a tunable spectral range with high transmission in the neighboring spectral ranges. This functionality is obtained by using a two-dimensional, guided-mode resonance-based grating-waveguide metasurface that acts as a frequency-selective reflector, a spacer dielectric, and an absorbing oxide layer. Within the bandwidth of the excited guided-mode resonance excited at 1.82 textmum (with a full-width at half-maximum of 19 nm), we confirmed perfect absorption when light was incident from one of the two opposite directions, whereas in the other direction, perfect reflection was observed. The forward-to-backward absorption ratio reached as high as 60, while the thickness of the entire structure was on the order of the operating wavelength. In addition to the spectral tunability of the excited resonances and their bandwidths, our proposed device supports transparency windows with 65% transmission in the adjacent frequency bands. Our 2D grating is also verified to enable near-absolute insensitivity to the polarization state of incident light. Geometrical parameter modification also gives our design great tunability, as we also designed a device with a 300 nm absorption/reflection linewidth.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{antennae,

title = {Ultraminiature antennas combining subwavelength resonators and a very-high-ε uniform substrate: the case of lithium niobate},

author = {Andriy E Serebryannikov and M Gokkavas and T F Gundogdu and V Volski and G A E Vandenbosch and A Vasylchenko and E Ozbay},

url = {https://ieeexplore.ieee.org/document/9016372},

doi = {10.1109/TAP.2020.2975544},

year  = {2020},

date = {2020-01-01},

journal = {IEEE Transactions on Antennas and Propagation},

volume = {68},

pages = {5071 - 5081},

abstract = {Combining the effects of subwavelength resonators and very-high-permittivity substrates enables a high extent of miniaturization, even for very simple, split-loop resonators. Here, we demonstrate how requirements to the substrate's permittivity are connected with the desired extent of miniaturization and why materials with a relative permittivity of 30 <; ε <; 100, like lithium niobate, may offer a real possibility to miniaturize. For demonstration purposes, we designed, in line with this approach, an ultraminiature dual-band antenna to operate at 2.8 and 4.2 GHz. The antenna is fabricated using microfabrication techniques and studied experimentally. There is good agreement between the measurement and simulation results. The realized gain is about -5 dB for the first resonance, at which the size of the substrate-resonator block is λ/24. The obtained results demonstrate the potential of the suggested approach, which is expected to be applicable to a very wide class of subwavelength resonators and a wide variety of substrates with high permittivity.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{PhysRevB.102.134402,

title = {Spin-wave talbot effect in a thin ferromagnetic film},

author = {Mateusz Gołębiewski and Paweł Gruszecki and Maciej Krawczyk and Andriy E Serebryannikov},

url = {https://link.aps.org/doi/10.1103/PhysRevB.102.134402},

doi = {10.1103/PhysRevB.102.134402},

year  = {2020},

date = {2020-01-01},

journal = {Physical Review B},

volume = {102},

pages = {134402},

abstract = {The Talbot effect has been known in linear optics since the 19th century and has found various technological applications. In this paper, with the help of micromagnetic simulations, we demonstrate the self-imaging phenomenon for spin waves in a thin, out-of-plane and in-plane magnetized ferromagnetic film whose propagation is described by the Landau-Lifshitz nonlinear equation. We show that the main features of the obtained Talbot carpets for spin waves can be described, to a large extent, by the approximate analytical formulas yielded by the general analysis of the wave phenomena. Our results indicate a route to a feasible experimental realization of the Talbot effect at low and high frequencies and offer interesting effects and possible applications in magnonics.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}