Abstract

The electrical control of magnetism adds a new dimension to future spin-based information processing methods. The use of an electric field instead of electric current is expected to make ultra-low power driving devices possible [1-9]. Ferromagnetic semiconductors have been the central material for this kind of research field because their magnetic properties are a function of the carrier concentration. We have reported for the first time on the electric field control of the ferromagnetic phase transition and tuning of the Curie temperature by using (In,Mn)As, a ferromagnetic semiconductor [1]. We also reported on an electrical coercivity control, and an electric-field assisted magnetization switching was demonstrated by using it [2]. It was recently discovered that the magnetization direction can be controlled by controlling the magnetic anisotropy [3]. We believe that this opens up an entirely new route for electrical magnetization switching without using a magnetic field or current. Reports have even more recently been released on the electric field control of magnetic properties in even ferromagnetic metal thin films [4-9]. We found that the ferromagnetic phase transition can be induced in cobalt ultra-thin films by applying an electric field to them [7,8]. In this talk, I show that the experimental results of electric field control of various ferromagnetic properties in field effect structures with a channel made of III -V ferromagnetic semiconductors or 3d ferromagnetic transition metals.

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