We performed measurements of Py/Cu and Py/Ag lateral spin valves as function of injection current direction and magnitude. Above a 'critical' current, there is an unexpected dependence of spin injection on current direction. Positive currents show higher polarization of spin injection than negative. This implies that in addition to current-induced spin injection, there is a thermally induced injection from a spin-dependent Seebeck effect. A temperature gradient in the Py electrode, caused by Joule heating, is responsible for injecting excess spins into the non-magnetic channel. This effect has important consequences for understanding high-current spin-based devices, such as spin transfer torque devices.
@article{arxiv.1811.06112,
title = {Spin-dependent Seebeck effect in non-local spin valve devices},
author = {Mikhail Erekhinsky and Fèlix Casanova and Ivan K. Schuller and Amos Sharoni},
journal= {arXiv preprint arXiv:1811.06112},
year = {2018}
}