Searched for: faculty%3A%22Applied%255C%252BSciences%22
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Juarez-Acosta, I. (author), Olivares-Robles, M.A. (author), Bosu, S. (author), Sakuraba, Y. (author), Kubota, T. (author), Takahashi, S. (author), Takanashi, K. (author), Bauer, G.E.W. (author)
We model the charge, spin, and heat currents in ferromagnetic metal?normal metal?normal metal trilayer structures in the two current model, taking into account bulk and interface thermoelectric properties as well as Joule heating. The results include the temperature distribution as well as resistance-current curves that reproduce the observed...
journal article 2016
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Geprägs, S. (author), Kehlberger, A. (author), Coletta, F.D. (author), Qiu, Z. (author), Guo, E.J. (author), Schulz, T. (author), Mix, C. (author), Meyer, S. (author), Kamra, A. (author), Althammer, M. (author), Huebl, H. (author), Jakob, G. (author), Ohnuma, Y. (author), Adachi, H. (author), Barker, J. (author), Maekawa, S. (author), Bauer, G.E.W. (author), Saitoh, E. (author), Gross, R. (author), Goennenwein, S.T.B. (author), Kläui, M. (author)
Magnons are the elementary excitations of a magnetically ordered system. In ferromagnets, only a single band of low-energy magnons needs to be considered, but in ferrimagnets the situation is more complex owing to different magnetic sublattices involved. In this case, low lying optical modes exist that can affect the dynamical response. Here we...
journal article 2016
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Aqeel, A. (author), Vlietstra, N. (author), Heuver, J.A. (author), Bauer, G.E.W. (author), Noheda, B. (author), Van Wees, B.J. (author), Palstra, T.T.M. (author)
We report on the spin-Hall magnetoresistance (SMR) and spin Seebeck effect (SSE) in multiferroic CoCr2O4 (CCO) spinel thin films with Pt contacts. We observe a large enhancement of both signals below the spin-spiral (Ts=28K) and the spin lock-in (Tlock?in=14K) transitions. The SMR and SSE responses in the spin lock-in phase are one order of...
journal article 2015
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Schreier, M. (author), Chiba, T. (author), Niedermayr, A. (author), Lotze, J. (author), Huebl, H. (author), Geprags, S. (author), Takahashi, S. (author), Bauer, G.E.W. (author), Gross, R. (author), Goennenwein, S.T.B. (author)
We report the observation of current-induced spin torque resonance in yttrium iron garnet/platinum bilayers. An alternating charge current at GHz frequencies in the platinum gives rise to dc spin pumping and spin Hall magnetoresistance rectification voltages, induced by the Oersted fields of the ac current and the spin Hall effect-mediated spin...
journal article 2015
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Rameshti, B.Z. (author), Cao, Y. (author), Bauer, G.E.W. (author)
We apply Mie scattering theory to study the interaction of magnetic spheres with microwaves in cavities beyond the magnetostatic and rotating wave approximations. We demonstrate that both strong and ultrastrong coupling can be realized for stand alone magnetic spheres made from yttrium iron garnet (YIG), acting as an efficient microwave antenna....
journal article 2015
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Cao, Y. (author), Yan, P. (author), Huebl, H. (author), Goennenwein, S.T.B. (author), Bauer, G.E.W. (author)
We formulate a scattering theory to study magnetic films in microwave cavities beyond the independent-spin and rotating-wave approximations of the Tavis-Cummings model. We demonstrate that strong coupling can be realized not only for the ferromagnetic resonance mode, but also for spin-wave resonances; the coupling strengths are mode dependent...
journal article 2015
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Kamra, A. (author), Keshtgar, H. (author), Yan, P. (author), Bauer, G.E.W. (author)
We model the injection of elastic waves into a ferromagnetic film (F) by a nonmagnetic transducer (N). We compare the configurations in which the magnetization is normal and parallel to the wave propagation. The lack of axial symmetry in the former results in the emergence of evanescent interface states. We compute the energy-flux transmission...
journal article 2015
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Chiba, T. (author), Schreier, M. (author), Bauer, G.E.W. (author), Takahashi, S. (author)
The spin-torque ferromagnetic resonance (ST-FMR) in a bilayer system consisting of a magnetic insulator such as Y3Fe5O12 and a normal metal with spin-orbit interaction such as Pt is addressed theoretically. We model the ST-FMR for all magnetization directions and in the presence of fieldlike spin-orbit torques based on the drift-diffusion spin...
journal article 2015
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Kamra, A. (author), Witek, F.P. (author), Meyer, S. (author), Huebl, H. (author), Geprägs, S. (author), Gross, R. (author), Bauer, G.E.W. (author), Goennenwein, S.T.B. (author)
We measure the low-frequency thermal fluctuations of pure spin current in a platinum film deposited on yttrium iron garnet via the inverse spin Hall effect (ISHE)-mediated voltage noise as a function of the angle ? between the magnetization and the transport direction. The results are consistent with the fluctuation-dissipation theorem in terms...
journal article 2014
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Wang, S.Z. (author), Xia, K. (author), Bauer, G.E.W. (author)
We compute the thermoelectric transport parameterized by the Seebeck coefficient and thermal/electric conductance of random-alloy FeCo/MgO/FeCo(001) magnetic tunnel junctions (MTJs) from first principles using a generalized Landauer-Büttiker formalism. The thermopower is found to be typically smaller than those of Fe/MgO/Fe(001) MTJs. The ...
journal article 2014
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Joibari, F.K. (author), Blanter, Y.M. (author), Bauer, G.E.W. (author)
Nonresonant circularly polarized electromagnetic radiation can exert torques on magnetizations by the inverse Faraday effect (IFE). Here, we discuss the enhancement of IFE by spin-orbit interactions. We illustrate the principle by studying a simple generic model system, i.e., the quasi-one-dimensional ring in the presence of linear/cubic Rashba...
journal article 2014
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Chiba, T. (author), Bauer, G.E.W. (author), Takahashi, S. (author)
We formulate a theory of the ac spin Hall magnetoresistance in a bilayer system consisting of a magnetic insulator such as yttrium iron garnet and a heavy metal such as platinum. We derive expressions for the dc voltage generation based on the drift-diffusion spin model and quantum mechanical boundary condition at the interface that reveal a...
journal article 2014
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Skarsvag, H. (author), Bauer, G.E.W. (author), Brataas, A. (author)
We study the dynamics of spin valves consisting of two layers of magnetic insulators separated by a normal metal in the macrospin model. A current through the spacer generates a spin Hall current that can actuate the magnetization via the spin-transfer torque. We derive expressions for the effective Gilbert damping and the critical currents for...
journal article 2014
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Flipse, J. (author), Dejene, F.K. (author), Wagenaar, D. (author), Bauer, G.E.W. (author), Ben Youssef, J. (author), Van Wees, B.J. (author)
We report the observation of the spin Peltier effect (SPE) in the ferrimagnetic insulator yttrium iron garnet (YIG), i.e., a heat current generated by a spin current flowing through a platinum (Pt)|YIG interface. The effect can be explained by the spin transfer torque that transforms the spin current in the Pt into a magnon current in the YIG....
journal article 2014
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Zhou, Y. (author), Jiao, H. (author), Chen, Y. (author), Bauer, G.E.W. (author), Xiao, J. (author)
We develop a self-consistent theory for current-induced spin-wave excitations in normal metal/magnetic insulator bilayer structures. We compute the spin-wave dispersion and dissipation, including dipolar and exchange interactions in the magnet, the spin diffusion in the normal metal, as well as the surface anisotropy, spin-transfer torque, and...
journal article 2013
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Weiler, M. (author), Althammer, M. (author), Schreier, M. (author), Lotze, J. (author), Pernpeintner, M. (author), Meyer, S. (author), Huebl, H. (author), Gross, R. (author), Kamra, A. (author), Xiao, J. (author), Chen, Y.T. (author), Jiao, H.J. (author), Bauer, G.E.W. (author), Goennenwein, S.T.B. (author)
We perform a quantitative, comparative study of the spin pumping, spin Seebeck, and spin Hall magnetoresistance effects, all detected via the inverse spin Hall effect in a series of over 20??yttrium???iron?garnet/Pt samples. Our experimental results fully support present, exclusively spin current-based, theoretical models using a single set of...
journal article 2013
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Yan, P. (author), Kamra, A. (author), Cao, Y. (author), Bauer, G.E.W. (author)
The angular momentum vector of a Heisenberg ferromagnet with isotropic exchange interaction is conserved, while under uniaxial crystalline anisotropy the projection of the total spin along the easy axis is a constant of motion. Using Noether's theorem, we prove that these conservation laws persist in the presence of dipole-dipole interactions....
journal article 2013
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Schreier, M. (author), Kamra, A. (author), Weiler, M. (author), Xiao, J. (author), Bauer, G.E.W. (author), Gross, R. (author), Goennenwein, S.T.B. (author)
We calculate the phonon, electron, and magnon temperature profiles in yttrium iron garnet/platinum bilayers by diffusive theory with appropriate boundary conditions, in particular taking into account interfacial thermal resistances. Our calculations show that in thin film hybrids, the interface magnetic heat conductance qualitatively affects the...
journal article 2013
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Joibari, F.K. (author), Blanter, Y.M. (author), Bauer, G.E.W. (author)
We study the transport of electrons through a single-mode quantum ring with electric-field induced Rashba spin-orbit interaction that is subject to an in-plane magnetic field and weakly coupled to electron reservoirs. Modeling a ring array by ensemble averaging over a Gaussian distribution of energy-level positions, we predict slow conductance...
journal article 2013
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Qaiumzadeh, A. (author), Bauer, G.E.W. (author), Brataas, A. (author)
We investigate the nonresonant all-optical switching of magnetization. We treat the inverse Faraday effect (IFE) theoretically in terms of the spin-selective optical Stark effect for linearly or circularly polarized light. In the dilute magnetic semiconductors (Ga,Mn)As, strong laser pulses below the band gap induce effective magnetic fields of...
journal article 2013
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