Magnetic random access memory device using current induced switching
Provided is a magnetic memory device that uses a current induced switching (CID) method. The magnetic memory device that uses a CID method includes a lower electrode, a magnetic resistance structure that is formed on the lower electrode which comprises a free layer whose widths of two sides are varied, and an upper electrode formed on the magnetic resistance structure.
1. A magnetic memory device, comprising:
a lower electrode;
a magnetic resistance structure on the lower electrode; and
an upper electrode on the magnetic resistance structure; wherein
the magnetic resistance structure includes a first free layer,
a distance between two sides of the first free layer in a width direction varies, and
the lower electrode, the upper electrode and the magnetic resistance structure, except for the first free layer, have a substantially different shape as the first free layer.
2. The magnetic memory device of claim 1 , wherein the two sides of the first free layer are concaved towards a center of the sides.
3. The magnetic memory device of claim 1 , wherein the distance between the two sides of the first free layer increases towards a center of the two sides and decreases away from the center of the sides.
4. The magnetic memory device of claim 1 , wherein the two sides of the first free layer are opposite one another and are convexed toward one another.
5. The magnetic memory device of claim 1 , wherein the first free layer has an elliptical structure.
6. The magnetic memory device of claim 1 , wherein the first free layer has four sides including two sides parallel to each other and two sides that are not parallel.
7. The magnetic memory device of claim 1 , wherein the first free layer has four sides including two sides having a width that decreases toward a center of the two sides.
8. The magnetic memory device of claim 1 , wherein the first free layer has four sides including two sides having a width that increases toward a center of the two sides, and then, decreases away from the center of the two sides.
9. The magnetic memory device of claim 1 , wherein the two sides of the first free layer are mirror images of one another.
10. The magnetic memory device of claim 1 , wherein the distance between the two sides of the first free layer in a width direction varies along a length of the two sides.
11. The magnetic memory device of claim 1 , wherein the magnetic resistance structure includes:
an anti-ferromagnetic layer on the lower electrode;
a fixed layer whose magnetization direction is fixed by the anti-ferromagnetic layer;
a non-magnetic layer on the fixed layer; and
the first free layer is on the non-magnetic layer.
12. The magnetic memory device of claim 1 , wherein the magnetic resistance structure includes:
the first free layer on the lower electrode;
a non-magnetic layer on the first free layer;
a second free layer on the non-magnetic layer; and
an anti-ferromagnetic layer on the second free layer and fixes the magnetization direction of the second free layer.