The Experts below are selected from a list of 324 Experts worldwide ranked by ideXlab platform

A N Slavin - One of the best experts on this subject based on the ideXlab platform.

  • damping of linear spin wave modes in magnetic nanostructures local nonlocal and coordinate dependent damping
    Physical Review B, 2018
    Co-Authors: Roman Verba, Vasil Tiberkevich, A N Slavin
    Abstract:

    A general perturbation theory for the description of weak damping of linear spin-wave modes in magnetic nanostructures is developed. This perturbative approach allows one to account for the usual uniform Gilbert damping, as well as for the spatially nonuniform (coordinate-dependent) and nonlocal (magnetization-texture-dependent) Gilbert-like dissipation mechanisms. Using the derived general expression, it is possible to calculate the damping rate of a particular spin-wave mode if the frequency and the spatial profile of this mode, along with the relevant parameters of a magnetic material, are known. The examples demonstrating the applications of the developed general formalism include (i) generalization of the damping rate of a spin-wave mode propagating in a magnetic sample for the case of a nonuniform static magnetization or/and bias magnetic field, (ii) calculation of a damping rate of a gyrotropic mode in a vortex-state magnetic nanodot, (iii) evaluation of the spin diffusion influence on the damping rate of spin-wave modes in a conducting ferromagnet, and (iv) calculation of damping rates of spin-wave modes in a Ferromagnetic Film in the presence of a spin pumping into an adjacent nonmagnetic metal layer. The developed formalism is especially useful in micromagnetic simulations, as it allows one to calculate damping rates of spin-wave modes based on the numerical solution of a conservative eigenmode problem.

  • influence of interfacial dzyaloshinskii moriya interaction on the parametric amplification of spin waves
    Applied Physics Letters, 2015
    Co-Authors: Roman Verba, Vasil Tiberkevich, A N Slavin
    Abstract:

    The influence of the interfacial Dzyaloshinskii-Moriya interaction (IDMI) on the parametric amplification of spin waves propagating in ultrathin Ferromagnetic Film is considered theoretically. It is shown that the IDMI changes the relation between the group velocities of the signal and idler spin waves in a parametric amplifier, which may result in the complete vanishing of the reversed idler wave. In the optimized case, the idler spin wave does not propagate from the pumping region at all, which increases the efficiency of the amplification of the signal wave and suppresses the spurious impact of the idler waves on neighboring spin-wave processing devices.

Agnes Barthelemy - One of the best experts on this subject based on the ideXlab platform.

  • tunnel magnetoresistance and robust room temperature exchange bias with multiferroic bifeo3 epitaxial thin Films
    Applied Physics Letters, 2006
    Co-Authors: M Bibes, S Cherifi, F Nolting, Benedicte Warotfonrose, S Fusil, G Herranz, C Deranlot, Eric Jacquet, K Bouzehouane, Agnes Barthelemy
    Abstract:

    The authors report on the functionalization of multiferroic BiFeO3 epitaxial Films for spintronics. A first example is provided by the use of ultrathin layers of BiFeO3 as tunnel barriers in magnetic tunnel junctions with La2∕3Sr1∕3MnO3 and Co electrodes. In such structures, a positive tunnel magnetoresistance up to 30% is obtained at low temperature. A second example is the exploitation of the antiFerromagnetic spin structure of a BiFeO3 Film to induce a sizable (∼60Oe) exchange bias on a Ferromagnetic Film of CoFeB at room temperature. Remarkably, the exchange bias effect is robust upon magnetic field cycling, with no indications of training.

Maciej Krawczyk - One of the best experts on this subject based on the ideXlab platform.

  • spin wave nonreciprocity and magnonic band structure in a thin permalloy Film induced by dynamical coupling with an array of ni stripes
    Physical Review B, 2017
    Co-Authors: M Mruczkiewicz, Piotr Graczyk, P Lupo, A O Adeyeye, G Gubbiotti, Maciej Krawczyk
    Abstract:

    An efficient way for control of the spin wave propagation in a magnetic medium is the use of periodic patterns known as magnonic crystals (MCs). However, the fabrication of MCs especially bicomponents, with periodicity in nanoscale, is a challenging task due to the requirement for sharp interfaces. An alternative method to circumvent this problem is to use homogeneous Ferromagnetic Film with a modified periodically surrounding. In this work we demonstrate that the magnonic band structure is formed in thin Py Film due to dynamical magnetostatic coupling with the array of Ni stripes. We show that the band gap width can be systematically tuned by changing separation between Film and stripes. We show also the effect of nonreciprocity, which is seen at the band gap edge which is shifted from the Brillouin zone boundary and also in nonreciprocal interaction of propagating spin waves in Py Film with the standing waves in Ni stripes. Our findings open a possibility for further investigation and exploitation of the nonreciprocity and band structure in magnonic devices.

  • influence of magnetic surface anisotropy on spin wave reflection from the edge of Ferromagnetic Film
    Physical Review B, 2015
    Co-Authors: Pawel Gruszecki, Yu S Dadoenkova, N N Dadoenkova, I L Lyubchanskii, J Romerovivas, K Y Guslienko, Maciej Krawczyk
    Abstract:

    We study propagation of the Gaussian beam of spin waves and its reflection from the edge of thin yttrium-iron-garnet Film with in-plane magnetization perpendicular to this edge. We have performed micromagnetic simulations supported by analytical calculations to investigate influence of the surface magnetic anisotropy present at the Film edge on the reflection, especially in the context of the Goos-Hanchen effect. We have shown the appearance of a negative lateral shift between reflected and incident spin wave beams' spots. This shift is particularly sensitive to the surface magnetic anisotropy value and is a result of the Goos-Hanchen shift which is sensitive to the magnitude of the anisotropy and of the bending of spin wave beam. We have demonstrated that the demagnetizing field provide graded increase of the refractive index for spin waves, which is responsible for the bending.

Mikhail Kostylev - One of the best experts on this subject based on the ideXlab platform.

  • exchange anisotropy pinning of a standing spin wave mode
    Physical Review B, 2011
    Co-Authors: Rhet Magaraggia, R L Stamps, K J Kennewell, Mikhail Kostylev, M Ali, D Greig, B J Hickey, C H Marrows
    Abstract:

    Standing spin waves in a thin Film are used as sensitive probes of interface pinning induced by an antiferromagnet through exchange anisotropy. Using coplanar waveguide Ferromagnetic resonance, pinning of the lowest energy spin-wave thickness mode in Ni80Fe20/Ir25Mn75 exchange-biased bilayers was studied for a range of Ir25Mn75 thicknesses. We show that pinning of the standing mode can be used to amplify, relative to the fundamental resonance, frequency shifts associated with exchange bias. The shifts provide a unique “fingerprint” of the exchange bias and can be interpreted in terms of an effective Ferromagnetic Film thickness and ferromagnet-antiferromagnet interface anisotropy. Thermal effects are studied for ultrathin antiFerromagnetic Ir25Mn75 thicknesses, and the onset of bias is correlated with changes in the pinning fields. The pinning strength magnitude is found to grow with cooling of the sample, while the effective Ferromagnetic Film thickness simultaneously decreases. These results suggest that exchange bias involves some deformation of magnetic order in the interface region.

  • spin wave tunnelling through a mechanical gap
    EPL, 2010
    Co-Authors: T Schneider, R L Stamps, A A Serga, B Hillebrands, A V Chumak, Mikhail Kostylev
    Abstract:

    We report on the experimental and theoretical investigation of spin-wave tunnelling through a mechanical gap in a Ferromagnetic Film. Samples with different gap widths were fabricated and the transmission of spin-wave pulses through the gaps was studied. Transmission through the gaps is possible due to the long-range character of the dipole-dipole interaction underlying dynamics of long-wavelength spin waves. By comparing our experimental results with the developed theoretical model, we demonstrate, that the local inhomogeneity of the static magnetisation and the internal field has a significant impact on the transmission.

  • spin wave Ferromagnetic Film combiner as a not logic gate
    Journal of Nanoelectronics and Optoelectronics, 2008
    Co-Authors: T Schneider, A A Serga, B Hillebrands, Mikhail Kostylev
    Abstract:

    An on-chip spin-wave combiner was fabricated by structuring a ferrimagnetic yttrium iron garnet Film. Interference of magnetostatic spin-wave pulses in the combiner was studied using time and space resolve Brillouin light scattering spectroscopy. This investigation demonstrates functionality of the combiner as a NOT logic gate. We believe that it is an important step towards implementation of all-spin-wave on-chip logical gates.

  • resonant and nonresonant scattering of dipole dominated spin waves from a region of inhomogeneous magnetic field in a Ferromagnetic Film
    Physical Review B, 2007
    Co-Authors: Mikhail Kostylev, A A Serga, T Schneider, T Neumann, B Leven, B Hillebrands, R L Stamps
    Abstract:

    The transmission of a dipole-dominated spin wave in a Ferromagnetic Film through a localized inhomogeneity in the form of a magnetic field produced by a dc through a wire placed on the Film surface was studied experimentally and theoretically. It was shown that the amplitude and phase of the transmitted wave can be simultaneously affected by the current induced field, a feature that will be relevant for logic based on spin wave transport. The direction of the current creates either a barrier or a well for spin wave transmission. The main observation is that the current dependence of the amplitude of the spin wave transmitted through the well inhomogeneity is nonmonotonic. The dependence has a minimum and an additional maximum. A theory was constructed to clarify the nature of the maximum. It shows that the transmission of spin waves through the inhomogeneity can be considered as a scattering process and that the additional maximum is a scattering resonance.

Jacob Linder - One of the best experts on this subject based on the ideXlab platform.

  • long ranged triplet supercurrent in a single in plane ferromagnet with spin orbit coupled contacts to superconductors
    Physical Review B, 2019
    Co-Authors: Johannes Rosok Eskilt, Morten Amundsen, Niladri Banerjee, Jacob Linder
    Abstract:

    © 2019 American Physical Society. By converting conventional spin-singlet Cooper pairs to polarized spin-triplet pairs, it is possible to sustain long-ranged spin-polarized supercurrents flowing through strong ferromagnets. Obtaining such a conversion via spin-orbit interactions, rather than magnetic inhomogeneities, has recently been explored in the literature. A challenging aspect with regard to experimental detection has been that in order for Rashba spin-orbit interactions, present, e.g., at interfaces due to inversion symmetry breaking, to generate such long-ranged supercurrents, an out-of-plane component of the magnetization is required. This limits the choice of materials and can induce vortices in the superconducting region complicating the interpretation of measurements. Therefore, it would be desirable to identify a way in which Rashba spin-orbit interactions can induce long-ranged supercurrents for purely in-plane rotations of the magnetization. Here, we show that this is possible in a lateral Josephson junction where two superconducting electrodes are placed in contact with a Ferromagnetic Film via two thin, heavy normal metals. The magnitude of the supercurrent in such a setup becomes tunable by the in-plane magnetization angle when using only a single magnetic layer. These results could provide a new and simpler way to generate controllable spin-polarized supercurrents than previous experiments which utilized complicated magnetically textured Josephson junctions.

  • long ranged triplet supercurrent in a single in plane ferromagnet with spin orbit coupled contacts to superconductors
    arXiv: Superconductivity, 2019
    Co-Authors: Johannes Rosok Eskilt, Morten Amundsen, Niladri Banerjee, Jacob Linder
    Abstract:

    By converting conventional spin-singlet Cooper pairs to polarized spin-triplet pairs, it is possible to sustain long-ranged spin-polarized supercurrents flowing through strongly polarized ferromagnets. Obtaining such a conversion via spin-orbit interactions, rather than magnetic inhomogeneities, has recently been explored in the literature. A challenging aspect with regard to experimental detection has been that in order for Rashba spin-orbit interactions, present e.g. at interfaces due to inversion symmetry breaking, to generate such long-ranged supercurrents, an out-of-plane component of the magnetization is required. This limits the choice of materials and can induce vortices in the superconducting region complicating the interpretation of measurements. Therefore, it would be desirable to identify a way in which Rashba spin-orbit interactions can induce long-ranged supercurrents for purely in-plane rotations of the magnetization. Here, we show that this is possible in a lateral Josephson junction where two superconducting electrodes are placed in contact with a Ferromagnetic Film via two thin, heavy normal metals. The magnitude of the supercurrent in such a setup becomes tunable by the in-plane magnetization angle when using only a single magnetic layer. These results could provide a new and simpler way to generate controllable spin-polarized supercurrents than previous experiments which utilized complicated magnetically textured Josephson junctions.