Patent ID: 7486545

Claim:
A method to write and store information in a magnetic random access memory (MRAM), comprising: providing a magnetic tunnel junction (MTJ) stack, including a first free layer and a first antiferromagnetic (AFM) layer; providing a magnetic reference stack, including a second free layer that is exchange coupled to a second AFM layer having a blocking temperature; positioning said MTJ and magnetic reference stacks so that said first free layer is magnetostatically coupled to said second free layer; positioning said magnetic reference stack so that it is at an intersection of a bit line and a word line; while heating said second AFM layer to a temperature above said blocking temperature, passing electric current through said bit line thereby magnetizing said second free layer in a direction; and then, while said bit line current is still present, allowing said second AFM layer to cool to a temperature below said blocking temperature whereby said second free layer remains magnetized in said direction.