Magnetic memory element with perpendicular enhancement layer
The present invention is directed to a magnetic memory element including a magnetic free layer structure having a variable magnetization direction perpendicular to a layer plane thereof; an oxide layer formed adjacent to the magnetic free layer structure; an insulating tunnel junction layer formed adjacent to the magnetic free layer structure opposite the oxide layer; a first magnetic reference layer formed adjacent to the insulating tunnel junction layer opposite the magnetic free layer structure; a second magnetic reference layer separated from the first magnetic reference layer by a perpendicular enhancement layer; an antiferromagnetic coupling layer formed adjacent to the second magnetic reference layer; and a magnetic fixed layer structure formed adjacent to the antiferromagnetic coupling layer. The first and second magnetic reference layers have a first invariable magnetization direction substantially perpendicular to layer planes thereof. The magnetic fixed layer structure has a second invariable magnetization direction substantially opposite to the first invariable magnetization direction.
1. A magnetic memory element comprising:
a magnetic free layer structure including one or more magnetic free layers that have a same variable magnetization direction substantially perpendicular to layer planes thereof;
an insulating tunnel junction layer formed adjacent to said magnetic free layer structure;
a magnetic reference layer structure including a first magnetic reference layer formed adjacent to said insulating tunnel junction layer and a second magnetic reference layer separated from said first magnetic reference layer by a non-magnetic perpendicular enhancement layer, said first and second magnetic reference layers having a first fixed magnetization direction substantially perpendicular to layer planes thereof;
an anti-ferromagnetic coupling layer formed adjacent to said second magnetic reference layer opposite said non-magnetic perpendicular enhancement layer;
a magnetic fixed layer structure formed adjacent to said anti-ferromagnetic coupling layer opposite said second magnetic reference layer, said magnetic fixed layer structure having a second fixed magnetization direction that is substantially perpendicular to a layer plane thereof and is substantially opposite to said first fixed magnetization direction; and
an oxide layer formed adjacent to said magnetic free layer structure opposite said insulating tunnel junction layer.
2. The magnetic memory element according to claim 1 , wherein said oxide layer is made of hafnium oxide.
3. The magnetic memory element according to claim 1 , wherein said oxide layer is made of magnesium oxide.
4. The magnetic memory element according to claim 1 , wherein said oxide layer is made of aluminum oxide.
5. The magnetic memory element according to claim 1 , wherein said oxide layer is made of a compound comprising oxygen and a transition metal with said transition metal selected from the group consisting of tantalum, zirconium, chromium, titanium, vanadium, niobium, molybdenum, and tungsten.
6. The magnetic memory element according to claim 1 , wherein said insulating tunnel junction layer includes magnesium oxide or titanium oxide or a combination thereof.
7. The magnetic memory element according to claim 1 , wherein said anti-ferromagnetic coupling layer is made of ruthenium, iridium, rhodium, or a combination thereof.
8. The magnetic memory element according to claim 1 , wherein said magnetic free layer structure includes a magnetic free layer comprising iron, cobalt, and boron.
9. The magnetic memory element according to claim 1 , wherein said magnetic free layer structure includes a first magnetic free layer and a second magnetic free layer with another non-magnetic perpendicular enhancement layer interposed therebetween, said first and second magnetic free layers having the same variable magnetization direction substantially perpendicular to layer planes of said first and second magnetic free layers.
10. The magnetic memory element according to claim 9 , wherein said first magnetic free layer is formed adjacent to said insulating tunnel junction layer and is made of a material comprising iron, cobalt, and boron.
11. The magnetic memory element according to claim 9 , wherein said second magnetic free layer is formed adjacent to said oxide layer and is made of a material comprising iron and cobalt.
12. The magnetic memory element according to claim 9 , wherein said another non-magnetic perpendicular enhancement layer is made of molybdenum.
13. The magnetic memory element according to claim 9 , wherein said another non-magnetic perpendicular enhancement layer is made of tantalum, hafnium, or tungsten.
14. The magnetic memory element according to claim 1 , wherein said non-magnetic perpendicular enhancement layer is made of molybdenum.
15. The magnetic memory element according to claim 1 , wherein said non-magnetic perpendicular enhancement layer is made of tantalum, hafnium, or tungsten.
16. The magnetic memory element according to claim 1 , wherein said first magnetic reference layer includes iron, cobalt, and boron.
17. The magnetic memory element according to claim 1 , wherein said second magnetic reference layer includes a multilayer structure formed by interleaving one or more layers of a first material with one or more layers of a second material, at least one of said first and second materials being magnetic.
18. The magnetic memory element according to claim 17 , wherein said first material is cobalt and said second material is platinum or nickel.
19. The magnetic memory element according to claim 1 , wherein said magnetic fixed layer structure includes a multilayer structure formed by interleaving one or more layers of a first material with one or more layers of a second material, at least one of said first and second materials being magnetic.
20. The magnetic memory element according to claim 19 , wherein said first material is cobalt and said second material is platinum or nickel.