THREE-DIMENSIONAL (3D) MAGNETIC MEMORY DEVICES COMPRISING A MAGNETIC TUNNEL JUNCTION (MTJ) HAVING A METALLIC BUFFER LAYER
A magnetic memory device includes a cylindrical core; a plurality of layers surrounding the cylindrical core; a first terminal connected to a first end of the cylindrical core; and a second terminal connected to a second end of the cylindrical core, opposite the first end, wherein the first terminal is configured to receive a first current flowing radially from the cylindrical core through the plurality of layers, the first current imparting a torque on, at least, a magnetization of an inner layer of the plurality of layers.
1 . A magnetic memory device, comprising:
a cylindrical core;
a plurality of layers surrounding the cylindrical core;
a first terminal connected to a first end of the cylindrical core; and
a second terminal connected to a second end of the cylindrical core, opposite the first end, wherein the first terminal is configured to receive a first current flowing radially from the cylindrical core through the plurality of layers, the first current imparting a torque on, at least, a magnetization of an inner layer of the plurality of layers.
2 . The magnetic memory device of claim 1 , wherein the magnetization of the inner layer changes from a first direction to a second direction when the first current satisfies a threshold.
3 . The magnetic memory device of claim 1 , wherein the second terminal is configured to receive a second current, imparting a Spin Hall Effect (SHE) around a circumference of the cylindrical core.
4 . The magnetic memory device of claim 3 , wherein the SHE imparted around the circumference of the cylindrica core contributes to the torque imparted on the magnetization of the inner layer of the plurality of layers.
5 . The magnetic memory device of claim 3 , wherein the magnetization of the inner layer is in a first chirality, and the SHE imparted around the circumference of the cylindrical core has a second chirality that is opposite to the first chirality.
6 . The magnetic memory device of claim 1 , wherein the plurality of layers comprise a first ferromagnetic layer, a spacer layer, and a second ferromagnetic layer.
7 . The magnetic memory device of claim 6 , wherein the inner layer is the first ferromagnetic layer.
8 . The magnetic memory device of claim 6 , wherein:
the first ferromagnetic layer surrounds the cylindrical core;
the spacer layer surrounds the first ferromagnetic layer; and
the second ferromagnetic layer surrounds the spacer layer.
9 . The magnetic memory device of claim 8 , wherein the first ferromagnetic layer is a storage layer and the second ferromagnetic layer is a reference layer.
10 . The magnetic memory device of claim 9 , further comprises a metallic buffer layer disposed between the cylindrical core and the first ferromagnetic layer.
11 . The magnetic memory device of claim 10 , wherein the metallic buffer layer comprises tantalum or tantalum nitride.
12 . The magnetic memory device of claim 8 , wherein the first ferromagnetic layer is a reference layer and the second ferromagnetic layer is a storage layer.
13 . The magnetic memory device of claim 12 , further comprises a metallic buffer layer disposed between the spacer layer and the second ferromagnetic layer.
14 . The magnetic memory device of claim 8 , further comprising a third terminal connected to the second ferromagnetic layer.
15 . The magnetic memory device of claim 14 , wherein the third terminal is configured to read out a stored memory state of the magnetic memory device.
16 . The magnetic memory device of claim 14 , wherein the third terminal is configured to receive the first current flowing radially from the cylindrical core through the plurality of layers.
17 . The magnetic memory device of claim 1 , wherein the cylindrical core is a non-magnetic metal.
18 . A magnetic memory device, comprising:
a cylindrical core;
a first ferromagnetic layer surrounds the cylindrical core;
a spacer layer surrounds the first ferromagnetic layer; and
a second ferromagnetic layer surrounds the spacer layer, wherein the second ferromagnetic layer is configured to receive a current flowing radially from the second ferromagnetic layer towards the cylindrical core, the current imparting a torque on, at least, magnetizations of the first ferromagnetic layer and the second ferromagnetic layer.
19 . The magnetic memory device of claim 18 , further comprises a metallic buffer layer disposed between the cylindrical core and the first ferromagnetic layer.
20 . The magnetic memory device of claim 18 , further comprises a metallic buffer layer disposed between the spacer layer and the second ferromagnetic layer.