57 research outputs found
Spin Hall magnetoresistance in antiferromagnet/heavy-metal heterostructures
We investigate the spin Hall magnetoresistance in thin film bilayer
heterostructures of the heavy metal Pt and the antiferromagnetic insulator NiO.
While rotating an external magnetic field in the easy plane of NiO, we record
the longitudinal and the transverse resistivity of the Pt layer and observe an
amplitude modulation consistent with the spin Hall magnetoresistance. In
comparison to Pt on collinear ferrimagnets, the modulation is phase shifted by
90{\deg} and its amplitude strongly increases with the magnitude of the
magnetic field. We explain the observed magnetic field-dependence of the spin
Hall magnetoresistance in a comprehensive model taking into account magnetic
field induced modifications of the domain structure in antiferromagnets. With
this generic model we are further able to estimate the strength of the
magnetoelastic coupling in antiferromagnets. Our detailed study shows that the
spin Hall magnetoresistance is a versatile tool to investigate the magnetic
spin structure as well as magnetoelastic effects, even in antiferromagnetic
multidomain materials
Time-dependent multistate switching of topological antiferromagnetic order in MnSn
The manipulation of antiferromagnetic order by means of spin-orbit torques
opens unprecedented opportunities to exploit the dynamics of antiferromagnets
in spintronic devices. In this work, we investigate the current-induced
switching of the magnetic octupole vector in the Weyl antiferromagnet MnSn
as a function of pulse shape, field, temperature, and time. We find that the
switching behavior can be either bistable or tristable depending on the
temporal structure of the current pulses. Time-resolved Hall effect
measurements reveal that MnSn switching proceeds via a two-step
demagnetization-remagnetization process caused by self-heating over a timescale
of tens of ns followed by cooling in the presence of spin-orbit torques. Our
results shed light on the switching dynamics of MnSn and prove the
existence of extrinsic limits on its switching speed.Comment: Rectified wrong order of MS and Supplemen
Control of nonlocal magnon spin transport via magnon drift currents
Spin transport via magnon diffusion in magnetic insulators is important for a
broad range of spin-based phenomena and devices. However, the absence of the
magnon equivalent of an electric force is a bottleneck. In this work, we
demonstrate the controlled generation of magnon drift currents in yttrium iron
garnet/platinum heterostructures. By performing electrical injection and
detection of incoherent magnons, we find magnon drift currents that stem from
the interfacial Dzyaloshinskii-Moriya interaction. We can further control the
magnon drift by the orientation of the magnetic field. The drift current
changes the magnon propagation length by up to 6 % relative to diffusion.
We generalize the magnonic spin transport theory to include a finite drift
velocity resulting from any inversion asymmetric interaction, and obtain
results consistent with our experiments.Comment: 6 pages, 3 figure
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