Patent ID: 8988935
Filing Date: 2015-03-24
Classification: G11C,H01F

Abstract:
1. Method for writing to a self-referenced MRAM cell comprising a magnetic tunnel junction comprising: a storage layer including a first ferromagnetic layer having a first storage magnetization, a second ferromagnetic layer having a second storage magnetization, and a non-magnetic coupling layer separating the first and second ferromagnetic layers; a sense layer having a free sense magnetization; and a tunnel barrier layer included between the sense and storage layers; the first and second ferromagnetic layers being arranged such that a dipolar coupling between the storage and the sense layers is substantially null; the magnetic tunnel junction further comprising an antiferromagnetic layer exchange coupling the second ferromagnetic layer such as to pin the second storage magnetization at a low temperature threshold and to free it at a second high temperature threshold; the method comprising the steps of: heating the magnetic tunnel junction to the high temperature threshold; applying a magnetic field to orientate the sense magnetization in a predefined direction corresponding to a desired direction of polarization for a spin-polarized current, wherein the magnitude of the applying a magnetic field is such that it can adjust the direction of the sense magnetization only and not the second storage magnetization; once the magnetic tunnel junction has reached the high temperature threshold, switching the first storage magnetization by passing a spin-polarized current in the magnetic tunnel junction, wherein the direction in which the first ferromagnetic magnetization is switched depends on the polarity of the spin-polarized current; the spin-polarized current being polarized only when passing in the sense layer in accordance with the direction of the sense magnetization, and being non-polarized before it passes through the sense layer.