Patent ID: 8811073

Claim:
A magnetic device comprising: a first magnetic layer having a fixed magnetisation direction; a second magnetic layer having a variable magnetisation direction, the magnetisation of the second magnetic layer being able to be orientated either parallel or anti-parallel to the magnetisation of the first magnetic layer; a first spacer separating the first magnetic layer and the second magnetic layer; a third magnetic layer having a variable magnetisation direction such as to change the magnetic device from a read mode to a write mode and conversely, the magnetisation of the third magnetic layer being able to be controlled in such a way that: in the read mode, the third magnetic layer has a magnetisation direction parallel or anti-parallel to the magnetisation direction of the first magnetic layer so as to subtract spin transfer torques exerted by the first magnetic layer and the third magnetic layer on the magnetisation of the second magnetic layer; in the write mode, the third magnetic layer has a magnetisation direction: parallel to the magnetisation direction of the first magnetic layer when the third magnetic layer has a magnetisation direction anti-parallel to the magnetisation direction of the first magnetic layer in read mode, or anti-parallel to the magnetisation direction of the first magnetic layer when the third magnetic layer has a magnetisation direction parallel to the magnetisation direction of the first magnetic layer in read mode; a second spacer separating the second magnetic layer and the third magnetic layer; a control system for the direction of magnetisation of the third magnetic layer configured to change the direction of magnetisation of the third magnetic layer without changing the direction of magnetisation of the second magnetic layer.