Magnetic memory element and storage device using the same
View Patent ↗A magnetic miniaturized memory element with improved thermal stability of magnetization includes a first magnetic layer, an insulating layer that is formed on the first magnetic layer, a second magnetic layer that is formed on the insulating layer, and an expanded interlayer insulating film that comes into contact with side surfaces of the first and second magnetic layers, where at least one of the first magnetic layer and the second magnetic layer is strained and deformed so as to be elongated in an easy magnetization axis direction of the first magnetic layer or the second magnetic layer or compressive strain remains in any direction in the plane of at least one of the first magnetic layer and the second magnetic layer.
1. A magnetic memory element comprising:
a lower electrode;
an upper electrode;
a magnetic tunnel junction portion between the lower electrode and the upper electrode, wherein the magnetic tunnel junction portion includes a first magnetic layer, an insulating layer on the first magnetic layer, and a second magnetic layer on the insulating layer; and
an interlayer insulating film configured to apply compressive stress to opposite sides of the first or second magnetic layers in a one-axis direction of an in-plane direction of the first or second magnetic layers so as to contract the first or second magnetic layer along the one-axis direction and elongate the first or second magnetic layer in an easy-magnetization direction.
2. The magnetic memory element of claim 1 , wherein at least one of the first or second magnetic layers is strained and deformed into an elliptical or rectangular in-plane shape defining a long axis associated with the easy-magnetization direction and a short axis such that the respective magnetic layer is elongated in a direction along the long axis direction of the in-plane shape.
3. The magnetic memory element of claim 1 , wherein the first or second magnetic layer is a single-layer film made of a rare earth-transition metal alloy or a multi-layered film of a rare earth-transition metal alloy and a spin-polarized film.
4. The magnetic memory element of claim 3 , wherein the first or second magnetic layer is a multi-layered film of a rare earth-transition metal alloy and a FeCo alloy thin film or a FeCoB alloy thin film.
5. The magnetic memory element of claim 1 , wherein the first or second magnetic layer is a single-layer granular perpendicular magnetization film or a multi-layered film of a granular perpendicular magnetization film and a spin-polarized film, and wherein the easy-magnetization direction corresponds to a perpendicular direction of the first or second magnetic layer.
6. The magnetic memory element of claim 1 , wherein:
the easy-magnetization direction is perpendicular to the first or second magnetic layers; and
the first or second magnetic layer has a circular in-plane shape.
7. The magnetic memory element of claim 1 , wherein:
the easy-magnetization direction is perpendicular to the first or second magnetic layers; and
the first or second magnetic layer has a square in-plane shape.
8. A storage device comprising:
a plurality of magnetic memory elements, each magnetic memory element including:
a lower electrode;
an upper electrode; and
a magnetic tunnel junction portion between the lower electrode and the upper electrode, wherein the magnetic tunnel junction portion includes a first magnetic layer, an insulating layer on the first magnetic layer, and a second magnetic layer on the insulating layer; and
a sealing package having the plurality of magnetic memory elements sealed therein, wherein the sealing package is configured to:
draw at least one of the first and second magnetic layers; and
contract at least one of the first and second magnetic layers in an in-plane direction.
9. The storage device of claim 8 , wherein at least one of the first or second magnetic layers is strained and deformed into an elliptical or rectangular in-plane shape defining a long axis and a short axis such that the respective magnetic layer is elongated in a direction along the long axis direction of the in-plane shape.
10. The storage device of claim 8 , further including a die frame on which a substrate having the plurality of the magnetic memory elements provided thereon is placed, wherein the sealing package has the die frame sealed therein.
11. The storage device of claim 8 , wherein the first magnetic layer or the second magnetic layer is a single-layer film made of a rare earth-transition metal alloy or a multi-layered film of a rare earth-transition metal alloy and a spin-polarized film.
12. The storage device of claim 11 , wherein the first magnetic layer or the second magnetic layer is a multi-layered film of a rare earth-transition metal alloy and a FeCo alloy thin film or a FeCoB alloy thin film.
13. The storage device of claim 8 , wherein the first magnetic layer or the second magnetic layer is a single-layer granular perpendicular magnetization film or a multi-layered film of a granular perpendicular magnetization film and a spin-polarized film.
14. A storage device comprising:
a plurality of magnetic memory elements; and
a sealing package having the plurality of magnetic memory elements sealed therein,
each magnetic memory element including:
a lower electrode;
an upper electrode; and
a magnetic tunnel junction portion between the lower electrode and the upper electrode, wherein the magnetic tunnel junction portion includes a first magnetic layer, an insulating layer on the first magnetic layer, and a second magnetic layer on the insulating layer;
wherein the sealing material is configured to impart strain that elongates the first or second magnetic layer of at least one of the magnetic memory elements in a direction perpendicular to a surface of the respective magnetic layer such that compressive stress is generated and remains in an in-plane direction of the respective magnetic layer.
15. The storage device of claim 14 , wherein the first magnetic layer and the second magnetic layer are perpendicular magnetization films, and wherein at least one of the first or second magnetic layers is strained and deformed so as to be elongated in a direction perpendicular to a surface of the respective magnetization film.
16. The storage of claim 14 , wherein the first magnetic layer and the second magnetic layer are in-plane magnetization films, and wherein at least one of the first or second magnetic layers is strained and deformed into an elliptical or rectangular in-plane shape defining a long axis and a short axis such that the respective magnetic layer is elongated in a direction along the long axis direction of the in-plane shape.
17. The storage device of claim 14 , wherein the first magnetic layer or the second magnetic layer is a single-layer film made of a rare earth-transition metal alloy or a multi-layered film of a rare earth-transition metal alloy and a spin-polarized film.
18. The storage device of claim 17 , wherein the first magnetic layer or the second magnetic layer is a multi-layered film of a rare earth-transition metal alloy and a FeCo alloy thin film or a FeCoB alloy thin film.
19. The storage device of claim 14 , wherein the first magnetic layer or the second magnetic layer is a single-layer granular perpendicular magnetization film or a multi-layered film of a granular perpendicular magnetization film and a spin-polarized film.
20. The storage device of claim 19 , wherein the first magnetic layer or the second magnetic layer is a multi-layered film of a granular perpendicular magnetization film and a FeCo alloy thin film or a FeCoB alloy thin film.