Towards thermally induced spin accumulation in Fe/GaAs structures*

We study non-local spin valves of semiconductor-ferromagnetic metal hybrid systems [1]. The epitaxially grown samples consist of a low doped GaAs transport channel with ultrathin Fe top contacts. Magnetic fields applied along the easy and hard axis show spin-valve and Hanle-type curves, respectively. The latter can be used to determine the spin-dephasing time in our samples [2]. We further investigate the potential of non-local spin valves for electrical detection of thermally induced spin accumulation in semiconductors. Thermal spin injection is driven by temperature gradients across interfaces between ferromagnetic and non-magnetic materials [3]. Common ways to establish the required temperature gradients are Joule heating and absorption of focused laser light. We present finite-element simulations of the temperature profile expected in our microdevices. This is of interest in the emerging field of spin caloritronics. \\ \text{[1] X. Lou \textit{et al.}, Nat. Phys. 3, 197-202 (2007)}\\ \text{[2] K. Olejn\'ik, \textit{et al.}, Phys. Rev. Lett. 109, 076601 (2012)}\\ \text{[3] A. Slachter, \textit{et al.}, Nat. Phys. 6, 879-882 (2010)}