Inverse spin Hall effect in the semiconductor (Ga,Mn)As at room temperature

Abstract

We report experiments demonstrating that a spin current can be converted into a charge current in a film of the paramagnetic semiconductor (Ga,Mn)As at room temperature by means of the inverse spin Hall effect. The spin currents are generated in a thin layer of permalloy (Py) by two different processes: spin-pumping effect (SPE) and spin Seebeck effect (SSE). In the first, we use microwave-driven ferromagnetic resonance of the Py film to generate a SPE spin current that is injected into the (Ga,Mn)As film either in direct contact with Py or through a thin layer of insulating antiferromagnetic NiO. In the second, we use the SSE in the longitudinal configuration in Py with no contamination by the Nernst effect made possible with the use of a thin layer of NiO between the Py and (Ga,Mn)As layers. The results of the two measurements are consistent with each other, and from them, we obtain a spin Hall angle for (Ga,Mn)As at room temperature of ${\ensuremath{\theta}}_{\mathrm{SH}}=(1.5\ifmmode\pm\else\textpm\fi{}0.5)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$, which is one order of magnitude larger than the values reported for $p$-Si and $n$-Ge at room temperature.