Multilayered vertical spin-orbit torque devices
A magnetic memory device includes a spin-orbit interaction active core having a number of layers stacked along a longitudinal axis and a magnetic junction extending around the longitudinal axis and substantially surrounding at least a portion of the spin-orbit interaction active core. The magnetic junction includes a free layer, a reference layer, and a tunnel barrier layer between the free layer and the reference layer.
1 . A magnetic memory device comprising:
a spin-orbit interaction active core comprising a plurality of layers stacked along a longitudinal axis, the plurality of layers comprising a first layer and a second layer on the first layer; and
a magnetic junction extending around the longitudinal axis and substantially surrounding at least a portion of the spin-orbit interaction active core, the magnetic junction comprising a free layer, a reference layer, and a tunnel barrier layer between the free layer and the reference layer,
wherein the magnetic junction surrounds the first layer and the second layer.
2 . The magnetic memory device of claim 1 , wherein the spin-orbit interaction active core comprises a plurality of the first layer and a plurality of the second layer alternately arranged on top of each other along the longitudinal axis.
3 . The magnetic memory device of claim 1 , wherein at least one of the first layer or the second layer comprises a nitride.
4 . The magnetic memory device of claim 3 , wherein the nitride is selected from the group consisting of titanium nitride (TiN), scandium nitride (ScN), aluminum nitride (AlN), vanadium nitride (VN), chromium nitride (CrN), or combinations thereof.
5 . The magnetic memory device of claim 1 , wherein at least one of the first layer or the second layer comprises a perovskite oxide.
6 . The magnetic memory device of claim 5 , wherein the perovskite oxide is selected from the group consisting of lanthanum aluminate (LaAlO 3 ), strontium titanate (SrTiO 3 ), bismuth ferrite (BiFeO 3 ), and combinations thereof.
7 . The magnetic memory device of claim 1 , wherein at least one of the first layer or the second layer comprises a material having a rutile structure.
8 . The magnetic memory device of claim 7 , wherein the material having the rutile structure is selected from the group consisting of ruthenium oxide (RuO 2 ), titanium dioxide (TiO 2 ), vanadium oxide (VO 2 ), and combinations thereof.
9 . The magnetic memory device of claim 1 , wherein at least one of the first layer or the second layer comprises B2 type iridium-aluminum (IrAl).
10 . The magnetic memory device of claim 1 , wherein one of the first layer or the second layer comprises a heavy metal, and wherein another one of the first layer or the second layer comprises a main group metal.
11 . The magnetic memory device of claim 10 , wherein the heavy metal is selected from the group consisting of platinum (Pt), tungsten (W), tantalum (Ta), and iridium (Ir), and wherein the main group metal is selected from aluminum (Al), germanium (Ge), gallium (Ga), and combinations thereof.
12 . A method of programming the magnetic memory device of claim 1 , the method comprising:
passing a current through the spin-orbit interaction active core in the longitudinal axis; and
exerting a spin orbit torque on the free layer of the magnetic junction in response to the current passing through the spin-orbit interaction active core, the spin orbit torque switching a magnetic state of the free layer.
13 . A method of manufacturing a magnetic memory device, the method comprising:
forming a spin-orbit interaction active core by alternately depositing a first layer and a second layer into a plurality of layers stacked along a longitudinal axis;
forming a magnetic junction extending around the longitudinal axis and substantially surrounding a portion of the spin-orbit interaction active core, comprising depositing, by atomic layer deposition, a free layer, a tunnel barrier layer on the free layer, and a reference layer on the tunnel barrier layer,
wherein the magnetic junction surrounds the first layer and the second layer.
14 . The method of claim 13 , wherein the forming the spin-orbit interaction active core further comprises selecting a number of each of the first and second layers, materials of the first and second layers, and thicknesses of the first and second layers to achieve a desired resistivity of the spin-orbit interaction active core along the longitudinal axis.
15 . The method of claim 13 , wherein the spin-orbit interaction active core comprises a plurality of the first layer and a plurality of the second layer alternately arranged on top of each other along the longitudinal axis.
16 . The method of claim 13 , wherein at least one of the first layer or the second layer comprises a nitride selected from the group consisting of titanium nitride (TiN), scandium nitride (ScN), aluminum nitride (AlN), vanadium nitride (VN), chromium nitride (CrN), or combinations thereof.
17 . The method of claim 13 , wherein at least one of the first layer or the second layer comprises a perovskite oxide selected from the group consisting of lanthanum aluminate (LaAlO 3 ), strontium titanate (SrTiO 3 ), bismuth ferrite (BiFeO 3 ), and combinations thereof.
18 . The method of claim 13 , wherein at least one of the first layer or the second layer comprises a material having a rutile structure selected from the group consisting of ruthenium oxide (RuO 2 ), titanium dioxide (TiO 2 ), vanadium oxide (VO 2 ), and combinations thereof.
19 . The method of claim 13 , wherein at least one of the first layer or the second layer comprises B2 type iridium-aluminum (IrAl).
20 . The method of claim 13 , wherein one of the first layer or the second layer comprises a heavy metal selected from the group consisting of platinum (Pt), tungsten (W), tantalum (Ta), and iridium (Ir), and wherein another one of the first layer or the second layer comprises a main group metal selected from aluminum (Al), germanium (Ge), gallium (Ga), and combinations thereof.