Tetragonal half metallic heusler compounds
A magnetoresistive random-access memory cell includes a templating layer. The templating layer includes a binary alloy having an alternating layer lattice structure. The cell further includes a half metallic Heusler layer including a half metallic Heusler material having a tetragonal lattice structure. The half metallic Heusler layer is located outward of the templating layer, and has a Heusler in-plane lattice constant that is different from an in-plane lattice constant in a cubic form of the half metallic Heusler material. A tunnel barrier is located outward of the half metallic Heusler layer, and a magnetic layer is located outward of the tunnel barrier.
1 . A magnetoresistive random-access memory cell, comprising:
a templating layer comprising a binary alloy having an alternating layer lattice structure;
a half metallic Heusler layer comprising a half metallic Heusler material having a tetragonal lattice structure, the half metallic Heusler layer being located over the templating layer, and having a Heusler in-plane lattice constant that is different from an in-plane lattice constant in a cubic form of the half metallic Heusler material;
a tunnel barrier located over the half metallic Heusler layer on a side of the half metallic Heusler layer opposite the templating layer; and
a magnetic layer located over the tunnel barrier on a side of the tunnel barrier opposite the half metallic Heusler layer.
2 . The magnetoresistive random-access memory cell of claim 1 , wherein:
the half metallic Heusler layer comprises a storage layer; and
the magnetic layer comprises a reference layer.
3 . The magnetoresistive random-access memory cell of claim 2 , wherein the half metallic Heusler material is selected from the group consisting of Mn 2 FeSb, Mn 2 CoAl, Mn 2 CoGe, Mn 2 CoSi, Mn 2 CuSi, Co 2 CrAl, Co 2 CrSi, Co 2 MnSb, and Co 2 MnSi.
4 . The magnetoresistive random-access memory cell of claim 3 , wherein the half metallic Heusler layer has a thickness of less than 5 nm.
5 . The magnetoresistive random-access memory cell of claim 3 , wherein the half metallic Heusler material comprises Mn 2 FeSb.
6 . The magnetoresistive random-access memory cell of claim 5 , wherein the half metallic Heusler layer has a thickness of less than 5 nm.
7 . The magnetoresistive random-access memory cell of claim 2 , wherein the tunnel barrier is selected from the group consisting of magnesium oxide and magnesium aluminum oxide.
8 . The magnetoresistive random-access memory cell of claim 2 , wherein the binary alloy is represented by A 1−x E x , wherein A is a transition metal element and E is a main group clement including at least one of aluminum and gallium, and x is in the range from 0.42 to 0.55.
9 . The magnetoresistive random-access memory cell of claim 1 , wherein:
the half metallic Heusler layer comprises a reference layer; and
the magnetic layer comprises a storage layer.
10 . The magnetoresistive random-access memory cell of claim 9 , wherein the half metallic Heusler material compound is selected from the group consisting of Mn 2 FeSb, Mn 2 CoAl, Mn 2 CoGe, Mn 2 CoSi, Mn 2 CuSi, Co 2 CrAl, Co 2 CrSi, Co 2 MnSb, and Co 2 MnSi.
11 . The magnetoresistive random-access memory cell of claim 10 , wherein the half metallic Heusler layer has a thickness of less than 5 nm.
12 . The magnetoresistive random-access memory cell of claim 10 , wherein the half metallic Heusler material comprises Mn 2 FeSb.
13 . The magnetoresistive random-access memory cell of claim 12 , wherein the half metallic Heusler layer has a thickness of less than 5 nm.
14 . The magnetoresistive random-access memory cell of claim 1 , wherein the alternating layer lattice structure of the templating layer comprises a cesium chloride structure.
15 . The magnetoresistive random-access memory cell of claim 1 , wherein the templating layer is nonmagnetic at room temperature.
16 . The magnetoresistive random-access memory cell of claim 1 , wherein:
the templating layer has a templating layer in-plane lattice constant; and
the Heusler in-plane lattice constant substantially matches the templating layer in-plane lattice constant.
17 . The magnetoresistive random-access memory cell of claim 16 , wherein the half metallic Heusler material has magnetization substantially perpendicular to the half metallic Heusler material.
18 . A magnetoresistive random-access memory array, comprising:
a plurality of bit lines and a plurality of complementary bit lines forming a plurality of bit line-complementary bit line pairs;
a plurality of word lines intersecting said plurality of bit line pairs at a plurality of cell locations; and
a plurality of magnetoresistive random-access memory cells located at each of said plurality of cell locations, each of said magnetoresistive random-access memory cells being electrically connected to a corresponding bit line and selectively interconnected to a corresponding one of said complementary bit lines under control of a corresponding one of said word lines, each of said plurality of magnetoresistive random-access memory cells comprising:
a templating layer comprising a binary alloy having an alternating layer lattice structure;
a half metallic Heusler layer comprising a half metallic Heusler material having a tetragonal lattice structure, the half metallic Heusler layer being located over the templating layer, and having a Heusler in-plane lattice constant that is different from an in-plane lattice constant in a cubic form of the half metallic Heusler material;
a tunnel barrier of located over the half metallic Heusler layer on a side of the half metallic Heusler layer opposite the templating layer; and
a magnetic layer located over the tunnel barrier on a side of the tunnel barrier opposite the half metallic Heusler layer.
19 . The magnetoresistive random-access memory array of claim 18 , wherein:
the half metallic Heusler layer comprises a storage layer; and
the magnetic layer comprises a reference layer.
20 . The magnetoresistive random-access memory array of claim 19 , wherein the half metallic Heusler material is selected from the group consisting of Mn 2 FeSb, Mn 2 CoAl, Mn 2 CoGe, Mn 2 CoSi, Mn 2 CuSi, Co 2 CrAl, Co 2 CrSi, Co 2 MnSb, and Co 2 MnSi.
21 . The magnetoresistive random-access memory array of claim 18 , wherein:
the half metallic Heusler layer comprises a reference layer; and
the magnetic layer comprises a storage layer.
22 . The magnetoresistive random-access memory array of claim 21 , wherein the half metallic Heusler material is selected from the group consisting of Mn 2 FeSb, Mn 2 CoAl, Mn 2 CoGe, Mn 2 CoSi, Mn 2 CuSi, Co 2 CrAl, Co 2 CrSi, Co 2 MnSb, and Co 2 MnSi.
23 . A method of operating a magnetoresistive random-access memory array, comprising:
providing a magnetoresistive random-access memory array, said array comprising:
a plurality of bit lines and a plurality of complementary bit lines forming a plurality of bit line-complementary bit line pairs;
a plurality of word lines intersecting said plurality of bit line pairs at a plurality of cell locations; and
a plurality of magnetoresistive random-access memory cells located at each of said plurality of cell locations, each of said magnetoresistive random-access memory cells being electrically connected to a corresponding bit line and selectively interconnected to a corresponding one of said complementary bit lines under control of a corresponding one of said word lines, each of said plurality of magnetoresistive random-access memory cells comprising:
a templating layer comprising a binary alloy having an alternating layer lattice structure;
a half metallic Heusler layer comprising a half metallic Heusler material having a tetragonal lattice structure, the half metallic Heusler layer being located outward of over the templating layer, and having a Heusler in-plane lattice constant that is different from an in-plane lattice constant in a cubic form of the half metallic Heusler material;
a tunnel barrier located over the half metallic Heusler layer on a side of the half metallic Heusler layer opposite the templating layer; and
a magnetic layer located over the tunnel barrier on a side of the tunnel barrier opposite the half metallic Heusler layer;
applying signals to said word lines to cause a first subset of said cells to store logical ones and a second subset of said cells to store logical zeroes; and
reading said stored logical ones and zeroes via said bit lines and said complementary bit lines.
24 . A method of forming a magnetoresistive random-access memory cell, comprising:
providing a templating layer comprising a binary alloy having an alternating layer lattice structure and having a templating layer in-plane lattice constant;
epitaxially growing a half metallic Heusler layer over the templating layer, the half metallic Heusler layer comprising a half metallic Heusler material, the half metallic Heusler layer being grown over the templating layer such that the Heusler material has a tetragonal lattice structure and a Heusler in-plane lattice constant that is different from an in-plane lattice constant in a cubic form of the half metallic Heusler material and which substantially matches the templating layer in-plane lattice constant;
forming a tunnel barrier over the half metallic Heusler layer, on a side of the half metallic Heusler layer opposite the templating layer; and
forming a magnetic layer over the tunnel barrier, on a side of the tunnel barrier opposite the half metallic Heusler layer.
25 . A hardware description language (HDL) design structure encoded on a machine-readable data storage medium, said HDL design structure comprising elements that when processed in a computer-aided design system generates a machine-executable representation of a magnetoresistive random-access memory cell, wherein said (HDL design structure) comprises:
a templating layer comprising a binary alloy having an alternating layer lattice structure;
a half metallic Heusler layer comprising a half metallic Heusler material having a tetragonal lattice structure, the half metallic Heusler layer being located over the templating layer, and having a Heusler in-plane lattice constant that is different from an in-plane lattice constant in a cubic form of the half metallic Heusler material;
a tunnel barrier located over the half metallic Heusler layer on a side of the half metallic Heusler layer opposite the templating layer; and
a magnetic layer located over the tunnel barrier on a side of the tunnel barrier opposite the half metallic Heusler layer.