Magnonics and Metamaterials (December 5-6)
Date: Wednesday 2018.12.05Speaker: M.Sc. Nandan Babu Kuttath PadiAuthors: N. Babu Kuttath Padi, A. Trzaskowska, S. Mielcarek, M. Zdunek, P. Graczyk, J. W. Kłos, M. KrawczykAffiliation: Faculty of Physics, Adam Mickiewicz University in Poznań, PoznańTitle: Magnons and phonons in CoFeB/Au multilayer structuresAbstract: Inelastic light scattering is a powerful method to study the dispersion relations of magnons and phonons. We determine the dispersion relation of thermal magnons and phonons which exist in the multilayered sample using Brillouin light scattering (BLS) spectroscopy in CoFeB/Au multilayer deposited on the silicon substrate with Ti and Au layers. In the backward scattering geometry, the dispersion relations of magnons and phonons are determined for different values of the magnetic field. The finite element method (FEM) is used for interpretation of the experimental results.
This work was supported by National Science Centre of Poland Grant No. UMO-2016/21/B/ST3/00452 and the EU’s Horizon 2020 Research and Innovation Program under Marie Sklodowska-Curie Grant Agreement No. 644348 (MagIC).
Date: Wednesday 2018.12.05Speaker: Grzegorz CentałaAffiliation:Faculty of Physics, Adam Mickiewicz University in Poznań, PoznańTitle: The effect of spin wave pinning on FMR frequency in periodic structuresAbstract: One of the greatest advantages of spin waves is high frequency associated with low energy loss, therefore spin waves are promising as prospective information carriers. However, the usability of the devices based on spin waves is dependent on the range of operating frequency. The customizable frequency range may be achieved by changes in structural parameters, hence we consider spin wave pinning as a relatively easy way to adjust the frequency. Numerical calculations were made for CoFeB stripes arranged in the horizontal plane. We checked how the change in the width, thickness, and distance between the stripes affects the FMR frequency. This work was supported by National Science Centre of Poland Grant No. UMO-2016/21/B/ST3/00452 and the EU’s Horizon 2020 Research and Innovation Program under Marie Sklodowska-Curie Grant Agreement No. 644348 (MagIC).
Date: Thursday 2018.12.06Speaker: Dr. Gabriel D. Chaves-O’FlynnAffiliation: Institute of Molecular Physics, Polish Academy of Sciences, PoznańTitle: Thermal Stability of Soft Ferromagnetic NanoringsAbstract: The thermal stability of ferromagnetic nanostructures is mostly determined by the height of the energy barrier between two micromagnetic configurations: a metastable state and the ground state. Few analytical models for the magnetization profile at the lowest barrier have been obtained. In this talk, I will present micromagnetic simulations perform to validate one of those cases: a model for magnetization reversal of ferromagnetic nanorings.
 Phys. Rev. B 73, 054413 (2006)
Date: Thursday 2018.12.06Speaker: Dr. Emerson Coy (invited speaker)Affiliation: Institute of Molecular Physics, Polish Academy of Sciences, PoznańTitle: High temperature magneto dielectric thin films with low magnetic dampingAbstract: Here we present multiferroic (ferromagnetic/ferroelectric) thin films of highly strained Bi(Fe0.5Mn0.5)O3 as the only known high-temperature magnetodielectric material with low Gilbert damping. We present the general functional properties of the material, as well as few previously unreported structural and functional properties. Finally, we will show the great potential of this perovskite for spintronic applications.
Date: Thursday 2018.12.06Speaker: Dr. Hubert GłowińskiAffiliation: Institute of Molecular Physics, Polish Academy of Sciences, PoznańTitle: Magnetization damping in polycrystalline CoFe filmsAbstract: Magnetization damping of polycrystalline thin films of the Co25Fe75 alloy was found to be very low reaching 1×10-3 and the intrinsic damping of this alloy is even lower achieving 5×10-4. Our study focuses on the influence of an adjacent layer on total damping. We found that only using Cu buffer we obtain low magnetization damping and we confirmed low value of intrinsic damping.
Date: Thursday 2018.12.06Speaker: Dr. Piotr Graczyk (invited speaker)Affiliation: Institute of Molecular Physics, Polish Academy of Sciences, PoznańTitle: Electric-field-driven enhancement of magnetization dynamics in magnetoelectric heterostructuressAbstract: We performed simulations of coupled charge-spin-magnetization dynamics in magnetoelectric heterostructure which consists of two high-permittivity dielectrics separated by two conducting ferromagnetic layers. The layers are magnetized either parallel or antiparallel to each other. We show that it is possible to affect magnetization dynamics with an ac voltage applied to such heterostructure. The effect is driven by the field-like and anti-damping spin transfer torques.
Date: Wednesday 2018.12.06Speaker: Dr. Batłomiej Graczykowski (invited speaker)Affiliation: NanoBioMedical Center, Adam Mickiewicz Univesity in Poznań, PoznańTitle: Elastic properties of few nanometers thick membranesAbstract: The performance gain-oriented nanostructurization has opened a new pathway for tuning mechanical features of solid matter vital for application and maintained performance. Simultaneously, the mechanical evaluation has been pushed down to dimensions way below 1 μm. In this work, by means of micro-Brillouin light scattering we determine the mechanical properties, that is, Young modulus and residual stress, of polycrystalline few nanometers thick MoS2 membranes in a simple, contact-less, nondestructive manner. The results show huge elastic softening compared to bulk MoS2, which is correlated with the sample morphology and the residual stress.
Date: Thursday 2018.12.06Speaker: Dr. Joachim Graefe (invited speaker)Affiliation: Max Planck Institute for Intelligent Systems, StuttgartTitle: Nanomagnetism in the X-Ray SpotlightAbstract: The X-ray microscopy allows the application of powerful spectroscopic techniques in length scales far smaller than possible with optical microcopy. Near Edge X-ray Absorption Fine Structure (NEXAFS) gives the possibilities to the element and chemically sensitive imaging, while X-ray Circular Magnetic Dichroism (XMCD) allows direct, highly sensitive detection of sample magnetization. These contrast mechanisms at spatial resolutions of below 15 nm, and even better-using emergent techniques like ptychography, combined with the possibility of using the time structure of synchrotron light for pump- and- probe imaging with time resolutions of <50 ps make x-ray microscopy a powerful tool.
 W. Chao et al.: Nature 435 (2005) 1210.
 D. A. Shapiro et al.: Nature Photonics 8 (2014) 765.
 S. Woo et al.: Nature Materials 15 (2016) 501.
 K. Litzius et al.: Nature Physics 13 (2017) 170.
 S. Wintz et al.: Nature Nanotechnology 11 (2016) 948.
Date: Thursday 2018.12.06Speaker: Dr. Paweł GruszeckiAffiliation: Faculty of Physics, Adam Mickiewicz University in Poznań, PoznańTitle: Reflection of spin wave beamsAbstract: Reflection of spin wave beams We present results of the theoretical investigation of the spin wave beam reflection off the ferromagnetic film’s edge and/or the gradually decreasing magnonic refractive index. In particular, we demonstrate the Goos-Hanchen and the mirage effects for spin waves. Furthermore, the scattering of the incident spin wave beam at the edge spin waves, which causes the excitation of secondary beams with the increased/decreased frequency, will be discussed, as well.
Date: Thursday 2018.12.06Speaker: Prof. Konstatin V. Guslienko (keynote speaker)Affiliation: Departament of Materials Physics, Faculty of Chemistry, University of the Basque Country, San SebastianTitle: Magnetic skyrmion stability and dynamicsAbstract: Magnetic skyrmion is a kind of topological soliton, a non-trivial inhomogeneous magnetization texture on the nanoscale. In this talk I focus on the skyrmion stability and spin excitations in ultrathin magnetic films and cylindrical magnetic dots. The skyrmions can be stabilized due to an interplay of the isotropic and Dzyaloshinskii-Moriya exchange interactions, out-of-plane magnetic anisotropy and magnetostatic interaction.
Date: Thursday 2018.12.06Speaker: Dr. hab. Jarosław W. KłosAffiliation: Faculty of Physics, Adam Mickiewicz University in Poznań, PoznańTitle: Hartman effect for spin waves in exchange regimeAbstract: Hartman effect for spin waves in exchange regime The Hartman effect is the wave phenomenon observed for the wave package tunneling through the barrier where the evanescent solutions exist. This effect is manifested by the saturation of group delay of tunneling wave package with increasing width of the barrier. We showed the possibility of existence of the Hartman effect for the exchange spin waves. We took into account the general Barnaś-Mills boundary conditions in order to calculate the transmission of spin wave through the anisotropy barrier. This work was supported by National Science Centre of Poland Grant No. UMO-2016/21/B/ST3/00452 and the EU’s Horizon 2020 Research and Innovation Program under Marie Sklodowska-Curie Grant Agreement No. 644348 (MagIC).
Date: Wednesday 2018.12.05Speaker: Dr. Dominika KuźmaAffiliation: Institute of Nuclear Physics, Polish Academy of Sciences, KrakówTitle: Modeling of configuration switching in systems of macrospinsAbstract: We study switching mechanisms between ferromagnetic and antiferromagnetic (F – AF) configurations in systems of elliptically shaped flat nanoparticles (macrospins) under a variable applied magnetic field. Using a software based on the dynamical matrix method we compute frequencies and the corresponding spin profiles for the spin waves. Of special interest are those in the gigahertz frequency region. Limits of stability of configurations are marked by soft spin waves. We present various possibilities of enhancing recovery of the most stable AF configuration in a homogeneous external field.
Date: Wednesday 2018.12.05Speaker: M.Sc. Filip Lisiecki (invited speaker)Affiliation: Institute of Molecular Physics, Polish Academy of Sciences, PoznańTitle: Reprogrammability and scalability of magnonic Fibonacci quasicrystalsAbstract:Magnonic quasicrystals exceed the possibilities of spin waves (SW) manipulation offered by regular magnonic crystals, because of their more complex SW spectra with fractal characteristics. Here, we show the reprogrammability property of 1D Fibonacci magnonic quasicrystals, which allows controlling the SWs transmission. We demonstrate this property in the structures of different elements sizes and thus show the scalability of this system down to the nanometer scale.
Date: Wednesday 2018.12.05Speaker: Prof. Tadeusz Lulek (invited speaker)Affiliation: Division of Mathematical Physics, Faculty of Physics, Adam Mickiewicz University in Poznań, PoznańTitle: A three-magnon qubit: an example of Galois symmetry of Bethe pseudoparticlesAbstract:We discuss a specific Bethe Ansatz solution [1,2] of the eigenproblem of the Heisenberg Hamiltonian for a magnetic isotropic ring with N = 7 nodes, at the centre k = 0 of the Brillouin zone, within the three-magnon sector r = 3, which implements an arithmetic qubit with the energy E = -5, and whose tho basis states are rigged string configurations. We demonstrate that this qubit exhibits Galois symmetry, represented by the dihedral group D6 permuting six admissible state paerameters of r = 3 Bethe pseudoparticles.
 T. Lulek, M. Łabuz, J. Milewski, and R. Stagraczyński, Physica B550, 294 (2018),
 J. Milewski, B. Lulek, T. Lulek, and R. Stagraczyński, Physica B434, 14 92014).
Date: Thursday 2018.12.06Speaker: Prof. Igor L. Lyubchanskii (keynote speaker)Authors: Y. S. Dadoenkova,1,2, N. N. Dadoenkova, 1,2, M. Krawczyk 3, I. L. Lyubchanskii2,4Affiliations:Title: Goos-Haenchen effect at Brillouin light scattering
1 Ulyanovsk State University, Ulyanovsk
2 Donetsk Institute for Physics and Engineering of the National Academy of Sciences of Ukraine
3 Faculty of Physics, Adam Mickiewicz University in Poznań, Poznań
4 Faculty of Physics, V. N. Karazin Kharkiv National University, KharkivAbstract: The lateral shift of reflected light beam, known as Goos-Haenchen effect, is theoretically studied for Brillouin light scattering by acoustic phonons and spin waves for Daemon-Eshbach geometry .
 Yuliya Dadoenkova, Nataliya Dadoenkova, Maciej Krawczyk and Igor Lyubchanskii, Goos-Hänchen effect for Brillouin light scattering by acoustic phonons, Optics Letters 43 (16), 3965 – 3968 (2018).Date: Thursday 2018.12.06Speaker: M.Sc. Szymon MieszczakAuthors: Jarosław W. KłosAffiliation: Faculty of Physics, Adam Mickiewicz University in Poznań, PoznańTitle: Driving magnetization dynamics in an on-demand magnonic crystal via the magnetoelastic interactionAbstract: Using spatial light interference of ultrafast laser pulses we impulsively generate a spatial modulation of the magnetization profile in an otherwise uniformly magnetized film, inducing the onset of magnonic bandstructure and its unique spatial distribution of magnetic excitations. The magnonic behaviour is visualized by the resonant interaction of these spin wave modes with elastics waves, which are simultaneously generated with, and phase-locked to, the magnonic profile. Calculation of the spin wave modal distribution in a laterally modulated magnetization landscape, using both the Plane Wave Method and micromagnetic simulations, provide a unified picture of the non-trivial precessional dynamics observed in our experiment. This work was supported by National Science Centre of Poland Grant No. UMO-2016/21/B/ST3/00452 and the EU’s Horizon 2020 Research and Innovation Program under Marie Sklodowska-Curie Grant Agreement No. 644348 (MagIC).Date: Wednesday 2018.12.05Speaker: M.Sc. Justyna RychłyAffiliation: Faculty of Physics, Adam Mickiewicz University in Poznań, PoznańTitle: Theoretical studies of spin wave dynamics in planar magnonic quasicrystalsAbstract:We have studied theoretically spin wave dynamics in planar magnonic quasicrystals and compared obtained results with the corresponding magnonic crystals. We have found that magnonic quasicrystals are characterized by complex spin wave spectra of a fractal nature and that spin waves of higher frequencies are localized in the bulk region of an intact system. Moreover, the lifetime of spin wave modes in magnonic crystals and magnonic quasicrystals will be presented. This work was supported the EU’s Horizon 2020 Research and Innovation Program under Marie Sklodowska-Curie Grant Agreement No. 644348 (MagIC).Date: Wednesday 2018.12.05Speaker: Dr. Paweł Sobieszczyk (invited speaker)Authors: P. Sobieszczyk, M. Krupiński, P. Zieliński, M. MarszałekAffiliation: Institute of Nuclear Physics, Polish Academy of Sciences, KrakówTitle: Magnetization reversal mechanisms in nanopatterned thin films with perpendicular magnetic anisotropyAbstract:Fabrication and modeling of patterned thin films with perpendicular magnetic anisotropy rise great interest due to their wide applications in magnetic storage, sensors and magnonic crystals. A good representative of such systems are well-ordered arrays of magnetic antidots and dots based on Co/Pd multilayers, where magnetic reversal mechanisms strongly depend on the array geometry [1, 2]. We attempt to understand and reproduce the observed magnetic properties and domain structure appearing in the arrays by micromagnetic simulations performed using Mumax3 software . In particular, changes in coercivity field, magnetic anisotropy constant and magnetic domain arrangement were studied and correlated with symmetry and size of nanostructures. The calculations show how edge effects, defects and inhomogeneity affect magnetization reversal and domain wall pinning mechanism, which helps to design similar patterned systems with the specific magnetic properties.
The numerical simulations were supported in part by the PL-Grid Infrastructure.
 M. Krupinski, D. Mitin, A. Zarzycki, A. Szkudlarek, M. Giersig, M. Albrecht and M. Marszałek, Magnetic transition from dot to antidot regime in large area Co/Pd nanopatterned arrays with perpendicular magnetization, Nanotechnology 2017, 28, 085302.
 C. Banerjee, Pawel Gruszecki, J. W. Klos, O. Hellwig, M. Krawczyk, and A. Barman, Magnonic band structure in a Co/Pd stripe domain system investigated by Brillouin light scattering and micromagnetic simulations, Phys. Rev. B 96, 024421
Vansteenkiste, A.; Leliaert, J.; Dvornik, M.; Helsen, M.; Garcia-Sanchez, F.; Van Waeyenberge, B., The Design and Verification of Mumax3. AIP Adv. 2014, 4, 107133.Date: Wednesday 2018.12.05Speaker: Krzysztof SzulcAffiliation: Faculty of Physics, Adam Mickiewicz University in Poznań, PoznańTitle: Magnetization reversal in the array of nanobarsAbstract: We investigate remagnetization in the two-dimensional array of permalloy nanobars with periodic and Fibonacci order. Hysteresis loops measured with magneto-optic Kerr effect microscopy shows particular behaviour of the structure in the magnetization reversal process. Monte Carlo simulations of macrospins in effective field and micromagnetic simulations as well as theoretical investigations of demagnetizing fields and dipolar interactions complemented experimental results explaining occurent phenomenons.Date: Thursday 2018.12.06Speaker: Dr. Żaneta Świątkowska-WarkockaAffiliation: Institute of Nuclear Physics, Polish Academy of Sciences, KrakówTitle: Laser synthesis of composite magnetic particlesAbstract: Iron or nickel and their oxide nanoparticles have received considerable attention due to their applications in magnetic, electronic, pigmental, catalyst and biomedical purposes. NiO/Ni and Fe3O4/FeO composite particles were prepared by a pulsed laser irradiation of oxide nanoparticles dispersed in liquid. The sizes of particles and their composition were controlled by tuning the laser parameters, such as laser fluence and/or irradiation time. Correlation between structure of obtained composites and their magnetic properties will be presented.Date: Wednesday 2018.12.05Speaker: Dr. hab. Aleksandra Trzaskowska (invited speaker)Affiliation: Faculty of Physics, Adam Mickiewicz University in Poznań, PoznańTitle: Periodic nanostructures investigated using BLSAbstract: Experimental and theoretical study of the phononic band gap in the hypersonic range for thermally activated Surface Acoustic Waves will be presented. Two dimensional phononic crystals have been studied by the Surface Brillouin Light Scattering. The experimental data will be compared with results of theoretical modeling by the Finite Element Method. This work was supported by National Science Centre of Poland Grant No. UMO-2016/21/B/ST3/00452.Date: Wednesday 2018.12.05Speaker: Miłosz ZdunekAffiliation: Faculty of Physics, Adam Mickiewicz University in Poznań, PoznańTitle: Investigation of magnons and phonons by BLS in bilayer substituted YIG samples?Abstract: We have investigated Surface Acoustic Waves (SAWs) and Backward Volume Magnetostatic Spin Waves (BVMSWs) in bilayer substituted YIG (Yttrium Iron Garnet) samples. The bottom layer is characterised by in-plane magnetisation direction, while the top layer’s magnetisation direction is out-of-plane. The spectra were obtained by Brillouin Light Scattering (BLS) method for different magnetic configurations. The dispersion relations for aforementioned waves has been designated by analyzing the spectral data.
This work was supported by National Science Centre of Poland Grant No. UMO-2016/21/B/ST3/00452 and the EU’s Horizon 2020 Research.Date: Thursday 2018.12.06Speaker: M.Sc. Mateusz ZelentAffiliation: Faculty of Physics, Adam Mickiewicz University in Poznań, PoznańTitle: Controlled motion of skyrmions in magnonic antidot latticesAbstract: Magnetic skyrmions are topologically protected nano-meter sized chiral spin textures with an out of plane magnetic domain at the center. Due to their various unique features such as stability given by their topology, they are considered as potential candidates for information carriers in next generation data storage devices, like racetrack memory. Therefore, it is crucial to be able to manipulate their current-induced motion in various directions. Magnetic antidot arrays can be used as a controller for skyrmion motion by using properly designed sequences of electrical current pulses, which marks a big leap toward skyrmion based devices, like logic gates, magnonics filters or demultiplexers.Date: Wednesday 2018.12.05Speaker: Prof. Piotr Zieliński (keynote speaker)Authors: P. Zieliński 1,2, D. Kuźma 1, P. Sobieszczyk1, F. Montoncello3Affiliations:Title: Is a discontinuous phase transition of second order possible in magnetic systems?
1 Institute of Nuclear Physics, Polish Academy of Sciences, Kraków
2 Institute of Nuclear Physics, Cracow University of Technology, Kraków, Poland
3 Department of Physics and Earth Sciences, CNISM Unit, University of Ferrara, FerraraAbstract:A transition between group-subgroup unrelated configurations is always discontinuous and often marked by a large hysteresis that impedes the switching of the configurations by varying a control parameter. This is e.g. characteristic of martensitic phase transitions. It will be shown that in some specific spin systems the hysteresis width may be reduced to zero in analogy to the second order phase transitions. Possible applications of such systems in the most efficiently switchable devices will be discussed.