Magnetic film, magnetoresistance effect element and magnetic memory
Provided are a magnetic film, a magnetoresistance effect element and a magnetic memory which take advantages of atop-pinned structure and a bottom-pinned structure, maintain perpendicular magnetic anisotropy of magnetic layers in a fixing layer and allow strong pinning even in an annealing treatment after a protective film is formed. A fixing layer of a magnetic film has a basic configuration in which a first magnetic layer ( 21 ), a first non-magnetic layer ( 31 ), a first Pt layer ( 41 ), a second magnetic layer ( 22 ) disposed adjacent to each other in this order. The magnetization directions of the first magnetic layer ( 21 ) and the second magnetic layer ( 22 ) are both a direction perpendicular to the film surface, and an antiferromagnetic coupling is formed between the first magnetic layer ( 21 ) and the second magnetic layer ( 22 ).
1. A magnetic film comprising:
a first magnetic layer;
a first non-magnetic layer which is provided adjacent to the first magnetic layer;
a first Pt layer which is provided adjacent to the first non-magnetic layer on a side opposite to the first magnetic layer; and
a second magnetic layer which is provided adjacent to the first Pt layer on the side opposite to the first non-magnetic layer, wherein
magnetization directions of the first magnetic layer and the second magnetic layer are both a direction perpendicular to a film surface,
an antiferromagnetic coupling is formed between the first magnetic layer and the second magnetic layer, and
a film thickness of the first Pt layer is in range of 0.25 nm to 0.9 nm.,
wherein the antiferromagnetic coupling between each of the first magnetic layer and second magnetic layer is maintained after an annealing treatment of between 300° C. to 400° C., and
a first adjustment layer disposed on and in contact with a side of the first magnetic layer opposite the first non-magnetic layer, and
the first adjustment layer contains Pt.
2. The magnetic film according to claim 1 , wherein the first magnetic layer and the second magnetic layer are Co.
3. The magnetic film according to claim 1 , wherein the first non-magnetic layer is Ir or Ru.
4. The magnetic film according to claim 3 , wherein the Ir film thickness of the first non-magnetic layer is 0.5±0.15 nm or 1.35±0.1 nm, or the Ru film thickness is 0.9±0.2 nm or 0.4±0.15 nm.
5. The magnetic film according to claim 1 , wherein the film thickness of the second magnetic layer is thicker than the film thickness of the first Pt layer.
6. The magnetic film according to claim 1 , further comprising a second non-magnetic layer which is provided adjacent to the second magnetic layer on the side opposite to the first Pt layer;
a second Pt layer which is provided adjacent to the second non-magnetic layer on the side opposite to the second magnetic layer, and
a third magnetic layer which is provided adjacent to the second Pt layer on the side opposite to the second non-magnetic layer, wherein
the magnetization direction of the third magnetic layer is a direction perpendicular to the film surface, and
an antiferromagnetic coupling is formed between the second magnetic layer and the third magnetic layer.
7. The magnetic film according to claim 6 , further comprising
a third non-magnetic layer which is provided adjacent to the third magnetic layer on the side opposite to the second Pt layer,
a third Pt layer which is provided adjacent to the third non-magnetic layer on the side opposite to the third magnetic layer, and
a fourth magnetic layer which is provided adjacent to the third Pt layer on the side opposite to the third non-magnetic layer, wherein
the magnetization direction of the fourth magnetic layer is a direction perpendicular to the film surface, and
an antiferromagnetic coupling is formed between the third magnetic layer and the fourth magnetic layer.
8. The magnetic film according to claim 7 , further comprising
a fourth non-magnetic layer which is provided adjacent to the fourth magnetic layer on the side opposite to the third Pt layer,
a fourth Pt layer which is provided adjacent to the fourth non-magnetic layer on the side opposite to the fourth magnetic layer, and
a fifth magnetic layer which is provided adjacent to the fourth Pt layer on the side opposite to the fourth non-magnetic layer, wherein
the magnetization direction of the fifth magnetic layer is a direction perpendicular to the film surface, and
an antiferromagnetic coupling is formed between the fourth magnetic layer and the fifth magnetic layer.
9. A magnetoresistance effect element comprising:
a first fixing layer including the magnetic film according to claim 1 ; and
a first barrier layer, wherein
the first barrier layer is disposed on the side of the first adjustment layer of the first fixing layer, and
the first adjustment layer is a Co/Pt multilayer film.
10. The magnetoresistance effect element according to claim 9 , wherein
the first magnetic layer and the second magnetic layer are Co,
the first non-magnetic layer is Ir or Ru, and
the Ir film thickness of the first non-magnetic layer is 0.5±0.15 nm or 1.35±0.1 nm, and
the Ru film thickness is 0.9±0.2 nm or 0.4±0.15 nm.
11. A magnetoresistance effect element comprising:
a second fixing layer including the magnetic film according to claim 1 ; and
a second barrier layer, wherein
the second barrier layer is disposed on the side opposite to the first adjustment layer of the second fixing layer, and
the first adjustment layer is a layer containing Pt as a main element.
12. A magnetic memory comprising the magnetoresistance effect element according to claim 9 .
13. The magnetic film according to claim 1 , wherein the second magnetic layer has an fcc (111) crystal structure.