Patent ID: 8503225

Claim:
Method for writing and reading more than two data bits to a magnetic random access memory (MRAM) cell comprising a magnetic tunnel junction formed from a read magnetic layer having a read magnetization, a tunnel barrier layer, and a storage layer; the storage layer that can be freely oriented at a high temperature threshold comprising a first storage ferromagnetic layer having a first storage magnetization, a second storage ferromagnetic layer having a second storage magnetization, and a storage anti-parallel coupling layer magnetically coupling the first and second storage magnetization; the method comprising: heating the magnetic tunnel junction to the high temperature threshold; orienting the first and second storage magnetization; and cooling the magnetic tunnel junction to a low temperature threshold to freeze the second storage magnetization; said orienting the first and second storage magnetization comprises the first storage magnetization forming a predetermined angle with respect to the second storage magnetization such as to reach a predetermined state resistance level of the magnetic tunnel junction determined by the orientation of the first storage magnetization relative to the read magnetization; and in that cooling the magnetic tunnel junction comprises freezing the second storage magnetization at the predetermined angle.