Patent ID: 8138758

Claim:
A method of operating a magnetoresistive device comprising a ferromagnetic region configured to exhibit magnetic anisotropy and to allow magnetisation thereof to be switched between at least first and second orientations and a gate, wherein the gate is operable to cause a change of orientation of magnetic anisotropy only through capacitive coupling to the ferromagnetic region, the method comprising: applying an electric field pulse to the ferromagnetic region using the gate so as to vary charge carrier distribution in the ferromagnetic region and so cause orientation of magnetic anisotropy to change for switching magnetisation between the first and second orientations, wherein the electric field pulse has a duration, t, which is a multiple of a quarter of about t precess : t precess = 1 / f precess = 1 γ 2 ⁢ π ⁢ B A where γ is the gyromagnetic constant γ=gμ B / (2.2×1015mA −1 s −1 ) and B A is the magnetic anisotropy field of the ferromagnetic semiconductor such that the electric field pulse triggers precessional switching of the magnetisation between the first and second orientations.