MAGNETIC STACK WITH LAMINATED LAYER
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.