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.]

To provide a key monocrystalline magnetoresistance element necessary for accomplishing mass production and cost reduction for applying a monocrystalline giant magnetoresistance element using a Heusler alloy to practical devices. A monocrystalline magnetoresistance element of the present invention includes a silicon substrate 11, a base layer 12 having a B2 structure laminated on the silicon substrate 11, a first non-magnetic layer 13 laminated on the base layer 12 having a B2 structure, and a giant magnetoresistance effect layer 17 having at least one laminate layer including a lower ferromagnetic layer 14, an upper ferromagnetic layer 16, and a second non-magnetic layer 15 disposed between the lower ferromagnetic layer 14 and the upper ferromagnetic layer 16.

A magnetoresistance effect element includes a first ferromagnetic layer, a second ferromagnetic layer, and a nonmagnetic spacer layer 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 contains a metal compound having a half-Heusler type crystal structure, the metal compound contains a functional material, and X atoms, Y atoms, and Z atoms which form a unit lattice of the half-Heusler type crystal structure, and the functional material has an atomic number lower than an atomic number of any of the X atoms, the Y atoms, and the Z atoms.

A magnetoresistance effect element includes a first ferromagnetic layer, a second ferromagnetic layer, and a nonmagnetic spacer layer 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 contains a metal compound having a half-Heusler type crystal structure, the metal compound contains a functional material, and X atoms, Y atoms, and Z atoms which form a unit lattice of the half-Heusler type crystal structure, and the functional material has an atomic number lower than an atomic number of any of the X atoms, the Y atoms, and the Z atoms.

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, and the tunnel barrier layer has a spinel structure represented by a composition formula AGa.sub.2O.sub.x (0<x4), and an A-site is a non-magnetic divalent cation which is one or more selected from a group consisting of magnesium, zinc and cadmium.

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 AB.sub.2O.sub.x, 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.

The present invention relates to new multiferroic materials. More particularly, the present invention relates to new multiferroic single phase ceramic materials as well as to thin films formed from these materials, methods of preparing these materials and their use as multiferroic materials in electronic components and devices.

There is provided a magnetoresistive effect element having improved magnetoresistive effect. A magnetoresistive effect element MR includes a first ferromagnetic layer 4 as a fixed magnetization layer, a second ferromagnetic layer 6 as a free magnetization layer, and a nonmagnetic spacer layer 5 provided between the first ferromagnetic layer 4 and the second ferromagnetic layer 6. The nonmagnetic spacer layer 5 includes at least one of a first insertion layer 5A provided under the nonmagnetic spacer layer 5 and a second insertion layer 5C provided over the nonmagnetic spacer layer 5. The first insertion layer 5A and the second insertion layer 5C are made of Fe.sub.2TiSi.

A structure includes an electronically controllable ferromagnetic oxide structure that includes at least three layers. The first layer comprises STO. The second layer has a thickness of at least about 3 unit cells, said thickness being in a direction substantially perpendicular to the interface between the first and second layers. The third layer is in contact with either the first layer or the second layer or both, and is capable of altering the charge carrier density at the interface between the first layer and the second layer. The interface between the first and second layers is capable of exhibiting electronically controlled ferromagnetism.

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 AB.sub.2O.sub.x, 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.