|   | 
Details
   web
Records
Author (up) Gao, T.H.; Qaiumzadeh, A.; Troncoso, R.E.; Haku, S.; An, H.Y.; Nakayama, H.; Tazaki, Y.; Zhang, S.; Tu, R.; Asami, A.; Brataas, A.; Ando, K.
Title Impact of inherent energy barrier on spin-orbit torques in magnetic-metal/semimetal heterojunctions Type
Year 2023 Publication Nature Communications Abbreviated Journal Nat. Commun.
Volume 14 Issue 1 Pages
Keywords ELECTRONS; DRIVEN; TRANSPORT; DYNAMICS
Abstract Spintronic devices are based on heterojunctions of two materials with different magnetic and electronic properties. Although an energy barrier is naturally formed even at the interface of metallic heterojunctions, its impact on spin transport has been overlooked. Here, using diffusive spin Hall currents, we provide evidence that the inherent energy barrier governs the spin transport even in metallic systems. We find a sizable field-like torque, much larger than the damping-like counterpart, in Ni81Fe19/Bi0.1Sb0.9 bilayers. This is a distinct signature of barrier-mediated spin-orbit torques, which is consistent with our theory that predicts a strong modification of the spin mixing conductance induced by the energy barrier. Our results suggest that the spin mixing conductance and the corresponding spin-orbit torques are strongly altered by minimizing the work function difference in the heterostructure. These findings provide a new mechanism to control spin transport and spin torque phenomena by interfacial engineering of metallic heterostructures.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2041-1723 ISBN Medium
Area Expedition Conference
Notes WOS:001054831600006 Approved
Call Number UAI @ alexi.delcanto @ Serial 1886
Permanent link to this record
 

 
Author (up) Saji, C.; Troncoso, R.E.; Carvalho-Santos, V.L.; Altbir, D.; Nunez, A.S.
Title Hopfion-Driven Magnonic Hall Effect and Magnonic Focusing Type
Year 2023 Publication Physical Review Letters Abbreviated Journal Phys. Rev. Lett.
Volume 131 Issue 16 Pages 166702
Keywords MAGNETIC; SKYRMIONS
Abstract Hopfions are localized and topologically nontrivial magnetic configurations that have received considerable attention in recent years. In this Letter, we use a micromagnetic approach to analyze the scattering of spin waves (SWs) by magnetic hopfions. Our results evidence that SWs experience an electromagnetic field generated by the hopfion and sharing its topological properties. In addition, SWs propagating along the hopfion symmetry axis are deflected by the magnetic texture, which acts as a convergent or divergent lens, depending on the SWs' propagation direction. Assuming that SWs propagate along the plane perpendicular to the symmetry axis, the scattering is closely related to the Aharonov-Bohm effect, allowing us to identify the magnetic hopfion as a scattering center.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0031-9007 ISBN Medium
Area Expedition Conference
Notes WOS:001102983000014 Approved
Call Number UAI @ alexi.delcanto @ Serial 1922
Permanent link to this record
 

 
Author (up) Shiranzaei, M.; Troncoso, R.E.; Fransson, O.; Brataas, A.; Qaiumzadeh, A.
Title Thermal squeezing and nonlinear spectral shift of magnons in antiferromagnetic insulators Type
Year 2022 Publication New Journal of Physics Abbreviated Journal New J. Phys.
Volume 24 Issue 10 Pages 103009
Keywords magnon; antiferromagnet; thermal squeezing; magnon-magnon interaction; nonlinear effect; uniaxial and biaxial antiferromagnet; scattering of magnon
Abstract We investigate the effect of magnon-magnon interactions on the dispersion and polarization of magnon modes in collinear antiferromagnetic (AF) insulators at finite temperatures. In two-sublattice AF systems with uniaxial easy-axis and biaxial easy-plane magneto-crystalline anisotropies, we implement a self-consistent Hartree-Fock mean-field approximation to explore the nonlinear thermal interactions. The resulting nonlinear magnon interactions separate into two-magnon intra- and interband scattering processes. Furthermore, we compute the temperature dependence of the magnon bandgap and AF resonance modes due to nonlinear magnon interactions for square and hexagonal lattices. In addition, we study the effect of magnon interactions on the polarization of magnon modes. We find that although the noninteracting eigenmodes in the uniaxial easy-axis case are circularly polarized, but in the presence of nonlinear thermal interactions the U(1) symmetry of the magnon Hamiltonian is broken. The attractive nonlinear interactions squeeze the low energy magnon modes and make them elliptical. In the biaxial easy-plane case, on the other hand, the bare eigenmodes of low energy magnons are elliptically polarized but thermal nonlinear interactions squeeze them further. Direct measurements of the predicted temperature-dependent AF resonance modes and their polarization can be used as a tool to probe the nonlinear interactions. Our findings establish a framework for exploring the effect of thermal magnon interactions in technologically important magnetic systems, such as magnetic stability of recently discovered two-dimensional magnetic materials, coherent transport of magnons, Bose-Einstein condensation of magnons, and magnonic topological insulators.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1367-2630 ISBN Medium
Area Expedition Conference
Notes WOS:000865597200001 Approved
Call Number UAI @ alexi.delcanto @ Serial 1673
Permanent link to this record
 

 
Author (up) Vidal-Silva, N.; Troncoso, R.E.
Title Time-dependent strain-tuned topological magnon phase transition Type
Year 2022 Publication Physical Review B Abbreviated Journal Phys. Rev. B
Volume 106 Issue 22 Pages 224401
Keywords INSULATOR; STATES
Abstract ollinear magnets in honeycomb lattices under the action of time-dependent strains are investigated. Given the limits of high-frequency periodically varying deformations, we derive an effective Floquet theory for spin systems that results in the emergence of a spin chirality. We find that the coupling between magnons and spin chirality depends on the details of the strain such as the spatial dependence and applied direction. Magnonic fluctuations about the ferromagnetic state are determined, and it is found that spatially homogeneous strains drive the magnon system into topologically protected phases. In particular, we show that certain uniform strain fields play the role of an out-of-plane nearest-neighbor Dzyaloshinskii-Moriya interaction. Furthermore, we explore the application of nonuniform strains, which lead to a confinement of magnon states that for uniaxial strains propagates along the direction that preserves translational symmetry. Our work demonstrates a direct way in which to manipulate the magnon spectrum based on time-dependent strain engineering that is relevant for exploring topological transitions in quantum magnonics.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9950 ISBN Medium
Area Expedition Conference
Notes WOS:000893212400003 Approved
Call Number UAI @ alexi.delcanto @ Serial 1704
Permanent link to this record