Patent ID: 7672093

Claim:
A process for the manufacture of an MTJ device, that includes a free layer having a magnetic moment, comprising: providing a substrate and depositing thereon a magnetic pinning layer; depositing a magnetically pinned layer on said pinning layer; depositing a tunnel barrier layer on said pinned layer; depositing on said tunnel barrier layer a composite free layer comprising first and second layers of NiFe whose magnetostriction constants are of opposite sign, thereby canceling one another; depositing on said composite free layer a first cap layer of NiFeHf; depositing on said first cap layer a second cap layer of Ru on Ta; and then heating said device for a time and at a temperature that are sufficient for oxygen trapped in said composite NiFe layer to diffuse into said NiFeHf layer, thereby sharpening an interface between said tunnel barrier layer and said composite free layer.