A seed layer stack with a uniform top surface having a peak to peak roughness of 0.5 nm is formed by sputter depositing an amorphous layer on a smoothing layer such as Mg where the latter has a resputtering rate 2 to 30 that of the amorphous layer. The seed layer stack may be repeated to give a laminate of two amorphous layers and two smoothing layers, and is advantageous for enhancing performance in magnetic tunnel junctions in embedded MRAMs, spintronic devices, or in read head sensors. A template layer such as NiCr may be formed on the uppermost smoothing layer to promote and maintain perpendicular magnetic anisotropy in an overlying magnetic layer during high temperature processing up to 400 C. The amorphous seed layer is SiN, TaN, or CoFeM where M is B or another element with a content that makes CoFeM amorphous as deposited.

A seed layer stack with a uniform top surface having a peak to peak roughness of 0.5 nm is formed by sputter depositing an amorphous layer on a smoothing layer such as Mg where the latter has a resputtering rate 2 to 30 that of the amorphous layer. The seed layer stack may be repeated to give a laminate of two amorphous layers and two smoothing layers, and is advantageous for enhancing performance in magnetic tunnel junctions in embedded MRAMs, spintronic devices, or in read head sensors. A template layer such as NiCr may be formed on the uppermost smoothing layer to promote and maintain perpendicular magnetic anisotropy in an overlying magnetic layer during high temperature processing up to 400 C. The amorphous seed layer is SiN, TaN, or CoFeM where M is B or another element with a content that makes CoFeM amorphous as deposited.

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 has a spinel structure in which cations are arranged in a disordered manner, and the tunnel barrier layer is expressed by a composition formula of (M.sub.1-xZn.sub.x)((T1).sub.2-y(T2).sub.y)O.sub.4 wherein M represents a non-magnetic divalent cation other than Zn, each of T1 and T2 represents a non-magnetic trivalent cation, and x and y represent a composition ratio in a region where composition ratios combined as follows ((1) to (5)) are vertexes, and the vertexes are connected by straight lines: (1) x=0.2, y=0.1, (2) x=0.8, y=0.1, (3) x=0.8, y=1.7, (4) x=0.6, y=1.7, and (5) x=0.2, y=0.7.

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 has a spinel structure in which cations are arranged in a disordered manner, and the tunnel barrier layer is expressed by a composition formula of (M.sub.1-xZn.sub.x)((T1).sub.2-y(T2).sub.y)O.sub.4 wherein M represents a non-magnetic divalent cation other than Zn, each of T1 and T2 represents a non-magnetic trivalent cation, and x and y represent a composition ratio in a region where composition ratios combined as follows ((1) to (5)) are vertexes, and the vertexes are connected by straight lines: (1) x=0.2, y=0.1, (2) x=0.8, y=0.1, (3) x=0.8, y=1.7, (4) x=0.6, y=1.7, and (5) x=0.2, y=0.7.

A laminated seed layer stack with a smooth top surface having a peak to peak roughness of 0.5 nm is formed by sequentially sputter depositing a first seed layer, a first amorphous layer, a second seed layer, and a second amorphous layer where each seed layer may be Mg and has a resputtering rate 2 to 30 that of the amorphous layers that are TaN, SiN, or a CoFeM alloy. A template layer that is NiCr or NiFeCr is formed on the second amorphous layer. As a result, perpendicular magnetic anisotropy in an overlying magnetic layer that is a reference layer, free layer, or dipole layer is substantially maintained during high temperature processing up to 400 C. and is advantageous for magnetic tunnel junctions in embedded MRAMs, spintronic devices, or in read head sensors. The laminated seed layer stack may include a bottommost Ta or TaN buffer layer.

A laminated seed layer stack with a smooth top surface having a peak to peak roughness of 0.5 nm is formed by sequentially sputter depositing a first seed layer, a first amorphous layer, a second seed layer, and a second amorphous layer where each seed layer may be Mg and has a resputtering rate 2 to 30 that of the amorphous layers that are TaN, SiN, or a CoFeM alloy. A template layer that is NiCr or NiFeCr is formed on the second amorphous layer. As a result, perpendicular magnetic anisotropy in an overlying magnetic layer that is a reference layer, free layer, or dipole layer is substantially maintained during high temperature processing up to 400 C. and is advantageous for magnetic tunnel junctions in embedded MRAMs, spintronic devices, or in read head sensors. The laminated seed layer stack may include a bottommost Ta or TaN buffer layer.

A magnetoresistance effect element includes first and second magnetic layers having a perpendicular magnetization direction, and a first non-magnetic layer disposed adjacent to the first magnetic layer and on a side opposite to a side on which the second magnetic layer is disposed. An interfacial perpendicular magnetic anisotropy exists at an interface between the first magnetic layer and the first non-magnetic layer, and the anisotropy causes the first magnetic layer to have a magnetization direction perpendicular to the surface of the layers. An atomic fraction of all magnetic elements to all magnetic and non-magnetic elements included in the second magnetic layer is smaller than that of the first magnetic layer.

A magnetoresistance effect element includes first and second magnetic layers having a perpendicular magnetization direction, and a first non-magnetic layer disposed adjacent to the first magnetic layer and on a side opposite to a side on which the second magnetic layer is disposed. An interfacial perpendicular magnetic anisotropy exists at an interface between the first magnetic layer and the first non-magnetic layer, and the anisotropy causes the first magnetic layer to have a magnetization direction perpendicular to the surface of the layers. An atomic fraction of all magnetic elements to all magnetic and non-magnetic elements included in the second magnetic layer is smaller than that of the first magnetic layer.

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.

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.