Spin polarised magnetic device

A magnetic device comprising:

• a magnetic reference layer with a fixed magnetisation direction located either in the plane of the reference layer or perpendicular to the plane of the reference layer;
• a magnetic storage layer with a variable magnetisation direction;
• a non-magnetic spacer separating said reference layer and said storage layer;
• a magnetic spin polarising layer with a direction perpendicular to that of said reference layer and located out of the plane of the spin polarising layer if the magnetisation of the reference layer is directed in the plane of the reference layer or in the plane of the spin polarising layer if the magnetisation of the reference layer is directed perpendicular to the plane of the reference layer;
• means for passing a current of electrons through and perpendicular to the layers;
• wherein said variable magnetisation direction has two positions of equilibrium substantially following the axis defined by said fixed magnetisation direction of said reference layer, the spin transfer coefficient between said reference layer and said storage layer being higher than the spin transfer coefficient between said spin polarising layer and said storage layer in such a way that, when in the presence of a current of electrons
• the spin transfer between said spin polarising layer and said storage layer moves the magnetisation direction of said storage layer away from a first position of equilibrium parallel or anti-parallel to the magnetisation direction of said reference layer, and,
• the spin transfer between said reference layer and said storage layer causes, according to the direction of the current of electrons
• either the switching of the magnetisation direction of said storage layer towards a second position of equilibrium corresponding to a magnetisation direction of said storage layer opposite to the magnetisation direction of said storage layer in said first position of equilibrium if the direction of the current of electrons is in a first direction;
• or the reversal of the magnetisation direction of said storage layer towards its magnetisation direction in said first position of equilibrium if the direction of the current of electrons is in the direction opposite to the first direction.