Magnetic memory
According to one embodiment, a magnetic memory according to an embodiment includes a magnetoresistive effect element and a fourth magnetic layer which is provided on the side surface of the magnetoresistive effect element via an insulating film. The magnetoresistive effect element has a first magnetic layer of which the magnetization direction is variable, a second magnetic layer of which the magnetization direction fixed, a third magnetic layer of which the magnetization direction parallel to a film plane is variable, and an intermediate layer between the first magnetic layer and the second magnetic layer. The fourth magnetic layer collects a magnetic field generated from the end of the third magnetic layer.
1. A magnetic memory comprising:
a magnetoresistive effect element having a first magnetic layer of which the magnetization direction perpendicular to a film plane is variable, a second magnetic layer of which the magnetization direction perpendicular to a film plane is fixed, a third magnetic layer of which the magnetization direction parallel to a film plane is variable, and an intermediate layer between the first magnetic layer and the second magnetic layer, the third magnetic layer generating a magnetic field by a rotation of the magnetization of the third magnetic layer due to a first current flowing in the first, second, and third magnetic layers, a magnitude of the first current being equal to or larger than an inversion threshold of the magnetization direction of the first magnetic layer; and
a fourth magnetic layer which is provided on the side surface of the magnetoresistive effect element via an insulating film and which collects the magnetic field generated from the third magnetic layer, the collected magnetic field applied to the first magnetic layer, and the fourth magnetic layer isolated from the third magnetic layer by the insulating film provided between the third magnetic layer and the fourth magnetic layer.
2. The magnetic memory according to claim 1 , wherein
the fourth magnetic layer cylindrically covers the magnetoresistive effect element.
3. The magnetic memory according to claim 1 , wherein
the magnetoresistive effect element includes an antiferromagnetic layer which is provided between the second magnetic layer and the third magnetic layer, and which fixes the magnetization of the second magnetic layer.
4. The magnetic memory according to claim 1 , wherein
one end of the fourth magnetic layer in the stacking direction of the first, second and third magnetic layers is located between the top and bottom surfaces of the first magnetic layer.
5. The magnetic memory according to claim 1 , wherein
one end of the fourth magnetic layer in the stacking direction of the first, second and third magnetic layers is located between the top and bottom surfaces of the third magnetic layer.
6. The magnetic memory according to claim 1 , wherein
the height of one end of the fourth magnetic layer in the stacking direction of the first, second and third magnetic layers corresponds to the height of one end of the magnetoresistive effect element.
7. The magnetic memory according to claim 1 , further comprising:
a first electrode provided between a substrate and the bottom of the magnetoresistive effect element; and
a second electrode provided on the top of the magnetoresistive effect element.
8. The magnetic memory according to claim 7 , wherein
the lower end of the fourth magnetic layer is located lower than the top surface of the first electrode.
9. The magnetic memory according to claim 8 , wherein
the thickness of the insulating film between the lower end of the fourth magnetic layer and the substrate is smaller than the thickness of the first electrode.
10. The magnetic memory according to claim 7 , wherein
the lower end of the fourth magnetic layer is located higher than the top surface of the first electrode.
11. The magnetic memory according to claim 10 , wherein
the thickness of the insulating film between the lower end of the fourth magnetic layer and the substrate is greater than the thickness of the first electrode.
12. The magnetic memory according to claim 7 , wherein
the upper end of the fourth magnetic layer is located higher than the bottom surface of the second electrode.
13. The magnetic memory according to claim 7 , wherein
the upper end of the fourth magnetic layer is located lower than or equal to the bottom surface of the second electrode.
14. The magnetic memory according to claim 7 , further comprising:
an interlayer insulating film covering the magnetoresistive effect element and the fourth magnetic layer,
wherein the insulating film is provided between the second electrode and the interlayer insulating film.
15. The magnetic memory according to claim 1 , wherein
the fourth magnetic layer includes a slit.
16. The magnetic memory according to claim 1 , wherein
a material for the fourth magnetic layer is NiFe or CoFeB.
17. The magnetic memory according to claim 1 , wherein
a material for the third magnetic layer is NiFe or CoFeB.
18. The magnetic memory according to claim 1 , wherein
the third magnetic layer includes no magnetic anisotropy.
19. The magnetic memory according to claim 1 , wherein
the planar shape of the third magnetic layer is circular.
20. The magnetic memory according to claim 1 , wherein
a material for the insulating film is aluminum oxide or silicon nitride.