Current-driven magnetization reversal in a Rashba bulk ferromagnet

The Rashba effect is the spin band splitting due to broken inversion symmetry through spin-orbit coupling, typically observed at surface and interface. Recently, some noncentrosymmetryic crystals have been found to have the bulk Rashba bands that are larger than surface/interface ones. In Rashba systems the charge current generates the net spin accumulation, which is known as Rashba-Edelstein effect (REE), leading to the electrical manipulation of the magnetization. Although such a current-driven magnetization manipulation has so far been studied for surface or interface Rashba systems, REE in bulk Rashba bands may be efficient because the local magnetic moment is in contact with the accumulated spin moment of the conduction spin. Here, we observed current-driven magnetization reversal in Ge_1-xMn_xTe thin film, which is a bulk ferromagnetic Rashba semiconductor. The switching ratio of anomalous Hall resistivity does not decrease with the film thickness, indicating the spin accumulation stems not from the interface or surface but bulk Rashba spin splitting bands.