Possibility of electrostatic control of magnetic moments in ferromagnetic semiconductors

Semiconductor devices exploit electron charge to carry and process information, whereas magnetic materials make use of electron spin to store it. Hybridization of both the functions in one device is a goal that could be fully reached if we were able to manipulate magnetic moments by electric voltage. Having this in view we consider a rectangular island etched from a thin layer of a ferromagnetic semiconductor, which represents a single ferromagnetic domain. The island has suitably patterned Schottky gates deposited on the top of the layer. By applying a voltage to the gates, one could locally deplete carrier density beneath the gates and thus tailor ferromagnetic sub-domains of different shapes on the island. We show that it is possible in this manner to reverse the direction of magnetization of the island, which could constitute the principle of novel class of spintronic devices.