A magnetoresistance effect element according to an aspect of the present disclosure includes a first ferromagnetic layer as a magnetization fixed layer including a ferromagnetic Heusler alloy, a second ferromagnetic layer as a magnetization free layer including a ferromagnetic Heusler alloy, and a nonmagnetic spacer layer provided between the first ferromagnetic layer and the second ferromagnetic layer, and the nonmagnetic spacer layer includes a nonmagnetic Fe group, Co group, or Ni group Heusler alloy.

A magnetoresistive effect element includes a first ferromagnetic layer, a second ferromagnetic layer, a nonmagnetic layer, and at least one of a first nonmagnetic insertion layer provided directly on a lower surface of the nonmagnetic layer and a second nonmagnetic insertion layer provided directly on an upper surface of the nonmagnetic layer. The first nonmagnetic insertion layer and the second nonmagnetic insertion layer include an Ag alloy represented by General Formula (1): Ag.sub.X.sub.1- where X indicates one element selected from the group consisting of Al, Cu, Ga, Ge, As, Y, La, Sm, Yb, and Pt, and 0<<1.

Provided are magnetoresistance effect element and a Heusler alloy in which an amount of energy required to rotate magnetization can be reduced. The magnetoresistance effect element includes a first ferromagnetic layer, a second ferromagnetic layer, and a non-magnetic layer positioned between the first ferromagnetic layer and the second ferromagnetic layer, in which at least one of the first ferromagnetic layer and the second ferromagnetic layer is a Heusler alloy in which a portion of elements of an alloy represented by Co.sub.2Fe.sub.Z.sub. is substituted with a substitution element, in which Z is one or more elements selected from the group consisting of Mn, Cr, Al, Si, Ga, Ge, and Sn, and satisfy 2.3+, <, and 0.5<<1.9, and the substitution element is an element different from the Z element and has a smaller magnetic moment than Co.

A magnetoresistance effect element and a Heusler alloy in which a state change due to annealing does not easily occur. The element includes a first ferromagnetic layer, a second ferromagnetic layer, and a non-magnetic layer positioned between the first ferromagnetic layer and the second ferromagnetic layer, in which at least one of the first ferromagnetic layer and the second ferromagnetic layer is a Heusler alloy in which a portion of elements of an alloy represented by Co.sub.2Fe.sub.Z.sub. is substituted with a substitution element, in which Z is one or more elements selected from the group consisting of Al, Si, Ga, Ge, and Sn, and satisfy 2.3+, <, and 0.5<<1.9, and the substitution element is one or more elements selected from the group consisting of elements having a melting point higher than that of Fe among elements of Groups 4 to 10.

To provide a magnetoresistance effect element that can further increase an MR ratio (Magnetoresistance ratio) and an RA (Resistance Area product).

The magnetoresistance effect element includes a first ferromagnetic layer, a second ferromagnetic layer, and a non-magnetic layer positioned between the first ferromagnetic layer and the second ferromagnetic layer, and at least one of the first ferromagnetic layer and the second ferromagnetic layer is a Heusler alloy represented by the following General Formula (1):

Co.sub.2Fe.sub.X.sub.(1)

(in Formula (1), X represents one or more elements selected from the group consisting of Mn, Cr, Si, Al, Ga and Ge, and and represent numbers that satisfy 2.3+, <, and 0.5<<1.9).

Devices are described that include a multi-layered structure that comprises three layers. The first layer is a magnetic Heusler compound, the second layer (acting as a spacer layer) is non-magnetic at room temperature and comprises alternating layers of Ru and at least one other element E (preferably Al; or Ga or Al alloyed with Ga, Ge, Sn or combinations thereof), and the third layer is also a magnetic Heusler compound. The composition of the second layer is represented by Ru.sub.1xE.sub.x, with x being in the range from 0.45 to 0.55. An MRAM element may be constructed by forming, in turn, a substrate, the multi-layered structure, a tunnel barrier, and an additional magnetic layer (whose magnetic moment is switchable).

A magnetic tunnel junction (MTJ) is disclosed wherein a nitride diffusion barrier (NDB) has a L2/L1/NL or NL/L1/L2 configuration wherein NL is a metal nitride or metal oxynitride layer, L2 blocks oxygen diffusion from an adjoining Hk enhancing layer, and L1 prevents nitrogen diffusion from NL to the free layer (FL) thereby enhancing magnetoresistive ratio and FL thermal stability, and minimizing resistance x area product for the MTJ. NL is the uppermost layer in a bottom spin valve configuration, or is formed on a seed layer in a top spin valve configuration such that L2 and L1 are always between NL and the FL or pinned layer, respectively. In other embodiments, one or both of L1 and L2 are partially oxidized. Moreover, either L2 or L1 may be omitted when the other of L1 and L2 is partially oxidized. A spacer between the FL and L2 is optional.

A magnetoresistive effect element according to the present invention includes: a first ferromagnetic layer as a magnetization fixed layer; a second ferromagnetic layer as a magnetization free layer; and a nonmagnetic spacer layer provided between the first ferromagnetic layer and the second ferromagnetic layer. The nonmagnetic spacer layer comprises an Al alloy represented by General Formula (1), and thereby lattice mismatch between the nonmagnetic spacer layer and the first ferromagnetic layer and/or the second ferromagnetic layer is reduced, compared to lattice mismatch when the nonmagnetic spacer layer is formed of Al.
Al.sub.X.sub.1-(1)
[wherein, X indicates one element selected from the group consisting of Li, N, Mg, Si, Sc, Cr, Fe, Ni, Cu, Zn, Ga, Ge, Zr, Ru, Pd, Ag, Sn, W, Pt, Au and Th, and is 0.5<<1.]

A device is disclosed. The device includes a tetragonal Heusler compound of the form Mn.sub.3-xCo.sub.xGe, wherein 0<x1, wherein Co accounts for at least 0.4 atomic percent of the Heusler compound. The device also includes a substrate oriented in the direction (001) and of the form YMn.sub.1+d, wherein Y includes an element selected from the group consisting of Ir and Pt, and 0d4. The tetragonal Heusler compound and the substrate are in proximity with each other, thereby allowing spin-polarized current to pass from one through the other. In one aspect, the device also includes a multi-layered structure that is non-magnetic at room temperature. The structure includes alternating layers of Co and E. E includes at least one other element that includes Al. The composition of the structure is represented by Co.sub.1-yE.sub.y, with y being in the range from 0.45 to 0.55.

A magnetic memory device includes a buffer layer on a substrate, a magnetic tunnel junction structure including a fixed layer structure, a tunnel barrier, and a free layer that are sequentially arranged on the buffer layer, and a spin-orbit torque (SOT) structure on the magnetic tunnel junction structure and including a topological insulator material, wherein the free layer includes a Heusler material.