Nonlocal spin Seebeck effect in the bulk easy-plane antiferromagnet NiO

Geert R. Hoogeboom*, Bart J. van Wees

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

We report the observation of magnon spin currents generated by the spin Seebeck effect (SSE) in a bulk single crystal of the easy-plane antiferromagnet NiO. A magnetic field induces a nondegeneracy and thereby an imbalance in the population of magnon modes with opposite spins. A temperature gradient then gives rise to a nonzero magnon spin current. This SSE is measured in both a local and a nonlocal geometry at 5 K in bulk NiO. The magnetic field dependence of the obtained signal is modeled by magnetic field splitting of the low-energy magnon modes, affecting the spin Seebeck coefficient. The relevant magnon modes at this temperature are linked to cubic anisotropy and magnetic dipole-dipole interactions. The nonlocal signal deviates from the expected quadratic Joule heating by saturating at a current from around 75 mu A in the injector. The magnon chemical potential does not decay exponentially with distance and inhomogeneities may be the result of local magnon accumulations.

Original languageEnglish
Article number214415
Number of pages6
JournalPhysical Review B
Volume102
Issue number21
DOIs
Publication statusPublished - 14-Dec-2020

Cite this