ABSTRACT
This chapter addresses the nature of the torque observed in metallic multilayers, bulk non-centrosymmetric magnets, and two-dimensional systems. The electric control of the magnetic order parameter is a powerful means to operate spin devices. While conventional spin transfer torque requires the existence of a spin polarizer and therefore a spin-valve configuration or a magnetic texture, an alter native approach has been intensively investigated in the past ten years. Spin-orbit coupling is a very powerful interaction that lies at the core of condensed matter physics and magnetism. The inverse spin-galvanic effect, present in all non-centrosymmetric materials, generates a non-equilibrium effective magnetic field whose direction is determined by the symmetry of the structure. The three-dimensional topological insulators are a new class of materials that have an insulating bulk and spin-momentum-locked metallic surface states. The electrical control of magnetic domain walls is among the most active topics in spintronics.
