Spin Transport in a Magnetic Insulator with Zero Effective Damping

Abstract

Applications based on spin currents strongly profit from the control and reduction of their effective damping and their transport properties. We here experimentally observe magnon mediated transport of spin (angular) momentum through a 13.4 nm thin yttrium iron garnet film with full control of the magnetic damping via spin-orbit torque. Above a critical spin-orbit torque, the fully compensated damping manifests itself as an increase of magnon conductivity by almost two orders of magnitude. We compare our results to theoretical expectations based on recently predicted current induced magnon condensates and discuss other possible origins of the observed critical behaviour. arXiv:1812.01334v3 [cond-mat.mtrl-sci]

Observation of Magnon Polarization

“…Whereas a theoretical treatment is not available yet, the optical modes may be expected to play a similarly important role. The optical modes might also explain the observation of a reduced magnon conductivity [30].…”

All‐Electrical Magnon Transport Experiments in Magnetically Ordered Insulators

“…The experiments discussed in this section have been conducted on YIG/Pt heterostructures and are published in the study by Wimmer et al [181] To achieve magnetic damping compensation via SHE, spin current injection requires thin YIG films with a thickness of %10 nm. In principle, even thinner YIG films would be beneficial, but magnetic damping in such YIG films also considerably increases, compensating the gain obtained by a reduction in magnetic volume.…”

“…a-c) Adapted with permission. [181] Copyright 2019, American Physical Society. For þ 50 mT applied to the sample, A increases for I dc until at large I dc the slope drastically changes.…”

Static magnetic proximity effects and spin Hall magnetoresistance in Pt/Y3Fe5O12 and inverted Geprägs1, Klewe2, Meyer3 et al. 2020Phys. Rev. B12040View full textAdd to dashboardCite

“…This so-called spin Hall magnetoresistance (SMR) was further experimentally confirmed in a variety of HM/FMI heterostructures such as Pt/YIG [31,32,[34][35][36][37][38], Ta/YIG [35], Pt/Gd 3 Fe 5 O 12 [39], Pt/Fe 3 O 4 [32], Pt/NiFe 2 O 4 [32,40], Pt/CoFe 2 O 4 [41], and Pt/Cu 2 OSeO 3 [42] as well as using antiferromagnetic insulators NiO [43][44][45][46], Cr 2 O 3 [47,48], and α-Fe 2 O 3 [46,[49][50][51]. The exchange of spin angular momentum as the underlying mechanism of the SMR is further confirmed by Pt/YIG/Pt trilayer structures [52,53] and nonlocal transport experiments in Pt/YIG bilayer nanostructures [54][55][56].…”