Magnetoresistance effect element
AssigneeTDK Corporation
InventorTomoyuki SASAKI
Life of this patent
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Abstract
A magnetoresistance effect element has a first ferromagnetic metal layer, a second ferromagnetic metal layer, and a tunnel barrier layer that is sandwiched between the first and second ferromagnetic metal layers, the tunnel barrier layer is expressed by a chemical formula of AB2Ox, and has a spinel structure in which cations are arranged in a disordered manner, A represents a divalent cation that is either Mg or Zn, and B represents a trivalent cation that includes a plurality of elements selected from the group consisting of Al, Ga, and In.
Claims10
A magnetoresistance effect element comprising:
- a first ferromagnetic metal layer;
- a second ferromagnetic metal layer;
- and
- a tunnel barrier layer that is sandwiched between the first and second ferromagnetic metal layers,
- wherein the tunnel barrier layer has a spinel structure, wherein
- the tunnel barrier layer comprises:
- at least one lattice-matched portion that is lattice-matched with both of the first ferromagnetic metal layer and the second ferromagnetic metal layer;
- and at least one lattice-mismatched portion that is not lattice-matched with at least one of the first ferromagnetic metal layer and the second ferromagnetic metal layer, and
- when viewed as an inverse Fourier transform image in a stacking direction of a cross-sectional crystal lattice image of the interface between the tunnel barrier layer and the first and/or the second ferromagnetic metal layer, a lattice-matched portion is made up of a plurality of sequential, continuously-connected lattice lines, and a lattice-mismatched portion is made up of a plurality of sequential, non-continuously-connected lattice lines and/or no lattice lines.
A method of manufacturing a magnetoresistance effect element comprising the steps of:
- forming an under layer on a substrate;
- forming a first ferromagnetic metal layer on the under layer;
- forming a tunnel barrier layer on the first ferromagnetic metal layer;
- forming a second ferromagnetic metal layer on the tunnel barrier layer;
- and
- forming a cap layer on the second ferromagnetic metal layer, wherein
- the step of forming a tunnel barrier layer comprises the steps of:
- depositing a metal thin film on the first ferromagnetic metal layer;
- oxidizing the deposited metal thin film by plasma oxidation or natural oxidation by introducing oxide;
- and
- heat treating the oxidized metal thin film, and
- the step of oxidizing is performed after cooling the substrate to −70° C. to −30° C., and wherein
- the tunnel barrier layer comprises:
- at least one lattice-matched portion that is lattice-matched with both of the first ferromagnetic metal layer and the second ferromagnetic metal layer;
- and at least one lattice-mismatched portion that is not lattice-matched with at least one of the first ferromagnetic metal layer and the second ferromagnetic metal layer, and
- when viewed as an inverse Fourier transform image in a stacking direction of a cross-sectional crystal lattice image of the interface between the tunnel barrier layer and the first and/or the second ferromagnetic metal layer, a lattice-matched portion is made up of a plurality of sequential, continuously-connected lattice lines, and a lattice-mismatched portion is made up of a plurality of sequential, non-continuously-connected lattice lines and/or no lattice lines.
Dependencies are inferred from the claim text.