Patent ID: 8736004

Claim:
A MTJ element in a magnetic device, comprising: (a) a pinned layer formed on a substrate and having an AP2/coupling layer/AP1 configuration wherein the AP2 layer is a first ferromagnetic layer, the coupling layer enables anti-ferromagnetic coupling between the AP2 and AP1 layers, and AP1 is a composite ferromagnetic layer with a CoFeB layer contacting the coupling layer and a CoFe layer that interfaces with a tunnel barrier layer, the CoFe layer has a thickness less than a thickness of the CoFeB layer; (b) the tunnel barrier layer made of a metal oxide that forms a first interface with the AP1 layer; the tunnel barrier layer has a bottom portion with a first thickness and a certain number of unoxidized metal atoms, and a fully oxidized second portion formed on the first portion with a second thickness less than the first thickness; (c) a composite free layer having a FL1/FL2/FL3 or Fe/NiFeX stack of layers wherein FL1 is a first crystalline ferromagnetic layer that forms a second interface with the tunnel barrier layer along a surface that is opposite to the first interface, FL2 is a second crystalline ferromagnetic layer that is Fe, and FL3 is an amorphous NiFeX layer where X is one of Hf, Zr, Nb, Ta, or Mg, the amorphous NiFeX layer is the uppermost layer in the FL1/Fe/NiFeX or Fe/NiFeX stack.