Evidence for reversible control of magnetization in a ferromagnetic material by means of spin-orbit magnetic field

The current state of information technology accentuates the dichotomy between processing and storage of information, with logical operations carried out by charge-based devices and non-volatile memory based on magnetic materials. The main obstacle for a wider use of magnetic materials for information processing is the lack of efficient control of magnetization. Reorientation of magnetic domains is conventionally carried out by non-local external magnetic fields or by externally polarized currents(1-3). The efficiency of the latter approach is enhanced in materials where ferromagnetism is carrier-mediated(4), because in such materials the control of carrier polarization provides an alternative means for manipulating the orientation of magnetic domains. In some crystalline conductors, the charge current couples to the spins by means of intrinsic spin-orbit interactions, thus generating non-equilibrium electron spin polarization(5-11) tunable by local electric fields. Here, we show that magnetization can be reversibly manipulated by the spin-orbit-induced polarization of carrier spins generated by the injection of unpolarized currents. Specifically, we demonstrate domain rotation and hysteretic switching of magnetization between two orthogonal easy axes in a model ferromagnetic semiconductor.