This magnetoresistance effect element includes a first ferromagnetic layer, a second ferromagnetic layer, and a nonmagnetic layer provided between the first ferromagnetic layer and the second ferromagnetic layer. At least one of the first ferromagnetic layer and the second ferromagnetic layer has an alloy obtained by adding an additive element to a Heusler alloy. The additive element is any one or more elements selected from the group consisting of H, He, N, O, F, Ne, P, Cl, Ar, Kr, and Xe.

A magnetoresistance effect element having a large MR ratio is provided.

This magnetoresistance effect element includes: a first ferromagnetic layer; a second ferromagnetic layer; and a nonmagnetic layer. The first ferromagnetic layer includes a first layer and a second layer. The first layer is closer to the nonmagnetic layer than the second layer. The first layer has a Heusler alloy containing at least partially crystallized Co. The second layer contains a material different from the Heusler alloy and has at least a partially crystallized ferromagnetic material. The first layer and the second layer have added first atoms. The first atom is any one selected from the group consisting of Mg, Al, Cr, Mn, Ni, Cu, Zn, Pd, Cd, In, Sn, Sb, Pt, Au, and Bi.

A magnetoresistance effect element having a large MR ratio is provided.

This magnetoresistance effect element includes: a first ferromagnetic layer; a second ferromagnetic layer; and a nonmagnetic layer. The first ferromagnetic layer includes a first layer and a second layer. The first layer is closer to the nonmagnetic layer than the second layer. The first layer has a Heusler alloy containing at least partially crystallized Co. The second layer contains a material different from the Heusler alloy and has at least a partially crystallized ferromagnetic material. The first layer and the second layer have added first atoms. The first atom is any one selected from the group consisting of Mg, Al, Cr, Mn, Ni, Cu, Zn, Pd, Cd, In, Sn, Sb, Pt, Au, and Bi.

A layered thin film device, such as a MTJ (Magnetic Tunnel Junction) device can be customized in shape by sequentially forming its successive layers over a symmetrically curved electrode. By initially shaping the electrode to have a concave or convex surface, the sequentially formed layers conform to that shape and acquire it and are subject to stresses that cause various crystal defects to migrate away from the axis of symmetry, leaving the region immediately surrounding the axis of symmetry relatively defect free. The resulting stack can then be patterned to leave only the region that is relatively defect free.

A layered thin film device, such as a MTJ (Magnetic Tunnel Junction) device can be customized in shape by sequentially forming its successive layers over a symmetrically curved electrode. By initially shaping the electrode to have a concave or convex surface, the sequentially formed layers conform to that shape and acquire it and are subject to stresses that cause various crystal defects to migrate away from the axis of symmetry, leaving the region immediately surrounding the axis of symmetry relatively defect free. The resulting stack can then be patterned to leave only the region that is relatively defect free.

Disclosed herein are layered Heusler alloys. The layered Heusler alloys can comprise a first layer comprising a first Heusler alloy with a face-centered cubic (fcc) crystal structure and a second layer comprising a second Heusler alloy with a fcc crystal structure, the second Heusler alloy being different than the first Heusler alloy, wherein the first layer and the second layer are layered along a layering direction, the layering direction being the [110] or [111] direction of the fcc crystal structure, thereby forming the layered Heusler alloy.

Disclosed herein are layered Heusler alloys. The layered Heusler alloys can comprise a first layer comprising a first Heusler alloy with a face-centered cubic (fcc) crystal structure and a second layer comprising a second Heusler alloy with a fcc crystal structure, the second Heusler alloy being different than the first Heusler alloy, wherein the first layer and the second layer are layered along a layering direction, the layering direction being the [110] or [111] direction of the fcc crystal structure, thereby forming the layered Heusler alloy.

Devices are described that include a multi-layered structure that is non-magnetic at room temperature, and which comprises alternating layers of Co and at least one other element E (that is preferably Al; or Al alloyed with Ga, Ge, Sn or combinations thereof). The composition of this structure is represented by Co.sub.1-xE.sub.x, with x being in the range from 0.45 to 0.55. The structure is in contact with a first magnetic layer that includes a Heusler compound. An MRAM element may be formed by overlying, in turn, the first magnetic layer with a tunnel barrier, and the tunnel barrier with a second magnetic layer (whose magnetic moment is switchable). Improved performance of the MRAM element may be obtained by placing an optional pinning layer between the first magnetic layer and the tunnel barrier.

Devices are described that include a multi-layered structure that is non-magnetic at room temperature, and which comprises alternating layers of Co and at least one other element E (that is preferably Al; or Al alloyed with Ga, Ge, Sn or combinations thereof). The composition of this structure is represented by Co.sub.1-xE.sub.x, with x being in the range from 0.45 to 0.55. The structure is in contact with a first magnetic layer that includes a Heusler compound. An MRAM element may be formed by overlying, in turn, the first magnetic layer with a tunnel barrier, and the tunnel barrier with a second magnetic layer (whose magnetic moment is switchable). Improved performance of the MRAM element may be obtained by placing an optional pinning layer between the first magnetic layer and the tunnel barrier.

An object of the present invention is to provide a Magneto-Resistance (MR) element showing a high Magneto-Resistance (MR) ratio and having a suitable Resistance-Area (RA) for device applications. The MR element of the present invention has a laminated structure including a first ferromagnetic layer 16, a non-magnetic layer 18, and a second ferromagnetic layer 20 on a substrate 10, wherein the first ferromagnetic layer 16 includes a Heusler alloy, the second ferromagnetic layer 20 includes a Heusler alloy, the non-magnetic layer 18 includes a I-III-VI.sub.2 chalcopyrite-type compound semiconductor, and the non-magnetic layer 18 has a thickness of 0.5 to 3 nm, and wherein the MR element shows a Magneto-Resistance (MR) change of 40% or more, and has a resistance-area (RA) of 0.1 [m.sup.2] or more and 3 [m.sup.2] or less.