Magnetic stack with laminated layer

Abstract

A magnetic stack with a multilayer free layer having a switchable magnetization orientation, the free layer comprising a first ferromagnetic portion and a second ferromagnetic portion with an electrically conducting non-magnetic intermediate layer between the first portion and the second portion. The magnetic stack also includes a first ferromagnetic reference layer having a pinned magnetization orientation, a first non-magnetic spacer layer between the free layer and the first reference layer, a second ferromagnetic reference layer having a pinned magnetization orientation, and a second non-magnetic spacer layer between the free layer and the second reference layer.

1 . A magnetic stack comprising:
 a first ferromagnetic reference layer having a pinned magnetization orientation;   a free layer having a switchable magnetization orientation;
 a first non-magnetic, electrically insulating barrier layer; 
   a second non-magnetic, electrically insulating barrier layer; and   a second ferromagnetic reference layer having a pinned magnetization orientation,   wherein the first non-magnetic spacer layer is positioned between the first ferromagnetic reference layer and the free layer, the free layer is positioned between the first non-magnetic spacer layer and the second non-magnetic spacer layer, and the second non-magnetic spacer layer is positioned between the free layer and the second ferromagnetic reference layer.   
     
     
         2 . The magnetic stack of  claim 1 , wherein the first and second barrier layers independently comprise a crystalline material. 
     
     
         3 . The magnetic stack of  claim 2 , wherein both the first barrier layer and the second barrier layer comprise crystalline MgO. 
     
     
         4 . The magnetic stack of  claim 1 , wherein the first and second barrier layers have a thickness of from about 0.5 nm to about 1.5 nm. 
     
     
         5 . The magnetic stack of  claim 1 , wherein the material of the free layer has a saturation moment (Ms) that is at least 1000 emu/cc. 
     
     
         6 . The magnetic stack of  claim 1 , wherein the material of the free layer has a saturation moment (Ms) that is at least 1500 emu/cc. 
     
     
         7 . The magnetic stack of  claim 1 , wherein the free layer comprises Co 100-x-y Fe x B y , wherein x is greater than 30 and y is greater than 15. 
     
     
         8 . The magnetic stack of  claim 1 , wherein the magnetization orientations of the first ferromagnetic reference layer and the second ferromagnetic reference layer are opposite to one another. 
     
     
         9 . The magnetic stack of  claim 1 , wherein the first reference layer comprises an unbalanced synthetic antiferromagnetic coupled structure. 
     
     
         10 . The magnetic stack of  claim 1 , wherein the second reference layer comprises an unbalanced synthetic antiferromagnetic coupled structure. 
     
     
         11 . The magnetic stack of  claim 1 , wherein the magnetic stack is a magnetic tunnel junction memory cell. 
     
     
         12 . The magnetic stack of  claim 1 , wherein the magnetic stack is a magnetic read sensor in a recording head. 
     
     
         13 . A magnetic memory device comprising:
 a substrate having a source region and a drain region with a channel region therebetween;   a gate electrically between the channel region and a word line;   a magnetic memory cell electrically connected to one of the source region and the drain region, the magnetic cell comprising:
 a first ferromagnetic reference layer having a pinned magnetization orientation; 
 a free layer having a switchable magnetization orientation;
 a first non-magnetic, electrically insulating barrier layer; 
 
 a second non-magnetic, electrically insulating barrier layer; and 
 a second ferromagnetic reference layer having a pinned magnetization orientation,
 wherein the first non-magnetic spacer layer is positioned between the first ferromagnetic reference layer and the free layer, the free layer is positioned between the first non-magnetic spacer layer and the second non-magnetic spacer layer, and the second non-magnetic spacer layer is positioned between the free layer and the second ferromagnetic reference layer; 
 
   a first line electrically connected to the magnetic memory cell; and   a second line electrically connected to the other of the source region and the drain region.   
     
     
         14 . The magnetic stack of  claim 13 , wherein the first and second barrier layers independently comprise a crystalline material. 
     
     
         15 . The magnetic stack of  claim 13 , wherein both the first barrier layer and the second barrier layer comprise crystalline MgO. 
     
     
         16 . The magnetic stack of  claim 13 , wherein the first and second barrier layers have a thickness of from about 0.5 nm to about 1.5 nm. 
     
     
         17 . The magnetic stack of  claim 13 , wherein the material of the free layer has a saturation moment (Ms) that is at least 1500 emu/cc. 
     
     
         18 . The magnetic stack of  claim 13 , wherein the free layer comprises CO 100-x-y Fe x B y , wherein x is greater than 30 and y is greater than 15. 
     
     
         19 . The magnetic stack of  claim 1 , wherein the magnetization orientations of the first ferromagnetic reference layer and the second ferromagnetic reference layer are opposite to one another. 
     
     
         20 . A spin-torque magnetic memory device comprising:
 a substrate having a source region and a drain region with a channel region therebetween;   a gate electrically between the channel region and a word line;   a magnetic memory cell electrically connected to one of the source region and the drain region, the magnetic cell comprising:
 a first ferromagnetic reference layer having a pinned magnetization orientation; 
 a free layer having a switchable magnetization orientation;
 a first non-magnetic, electrically insulating barrier layer; 
 
 a second non-magnetic, electrically insulating barrier layer; and 
 a second ferromagnetic reference layer having a pinned magnetization orientation,
 wherein the first non-magnetic spacer layer is positioned between the first ferromagnetic reference layer and the free layer, the free layer is positioned between the first non-magnetic spacer layer and the second non-magnetic spacer layer, and the second non-magnetic spacer layer is positioned between the free layer and the second ferromagnetic reference layer, 
 wherein the magnetic memory cell has a resistance state, which can be switched via spin-transfer by passing a current through the magnetic memory cell; 
 
   a first line electrically connected to the magnetic memory cell; and   a second line electrically connected to the other of the source region and the drain region.