PLATINUM AND COBALT/COPPER-BASED MULTILAYER THIN FILM HAVING LOW SATURATION MAGNETIZATION AND FABRICATION METHOD THEREOF

1 . A perpendicular magnetic anisotropy multilayer thin film for magnetic random access memory, comprising:

a thin platinum layer and a thin cobalt-copper layer alternately deposited to form a multilayer thin film over a substrate,

wherein the cobalt-copper layer is thicker than the thin platinum layer.

2 . The perpendicular magnetic anisotropy multilayer thin film of claim 1 , wherein a content ratio of cobalt: copper in the thin cobalt-copper layers is 50:50 to 90:10 (atomic ratio).

3 . The perpendicular magnetic anisotropy multilayer thin film of claim 1 , wherein the multilayer thin film including the thin platinum layer and the thin cobalt-copper layer is repeatedly stacked over the substrate 2-10 turns.

4 . The perpendicular magnetic anisotropy multilayer thin film of claim 1 , wherein the multilayer thin film has a total thickness of 0.24-12.5 nm.

5 . The perpendicular magnetic anisotropy multilayer thin film of claim 1 , wherein the thickness ratio of the thin cobalt-copper layer to the thin platinum layer is 1˜4.1.

6 . The perpendicular magnetic anisotropy layer thin film of claim 1 , further comprising:

a stack of a buffer layer provided between the substrate and the multilayer thin film, and

a protective layer deposited over the multilayer thin film.

7 . The perpendicular magnetic anisotropy multilayer thin film of claim 6 , wherein each of the buffer layer, the seed layer, and the protective layer independently includes gold (Au), palladium (Pd), copper (Cu), platinum (Pt), tantalum (Ta), ruthenium (Ru), or a combination thereof.

8 . A method for fabricating a perpendicular magnetic anisotropy multilayer thin film for magnetic random access memory, the method comprising:

mixing cobalt with copper to prepare a mixed metal;

alternately depositing platinum and the mixed metal over a substrate to form a multilayer thin film, wherein the multilayer thin film includes a thin platinum layer and a thin cobalt-copper layer; and

heat-treating the multilayer thin film,

wherein the cobalt-copper layer is thicker than the thin platinum layer.

9 . The method of claim 8 , wherein the heat-treating is performed at a temperature between 150° C. and 550° C.

10 . The method of claim 8 , further comprising:

depositing a buffer layer and a seed layer over the substrate before depositing the multilayer thin film; and

depositing a protective layer over the multilayer thin film after depositing the multilayer thin film.

11 . The method of claim 8 , wherein a content ratio of cobalt:

copper in the thin cobalt-copper layer is 50:50 to 90:10 (atomic ratio).

12 . The method of claim 8 , wherein the heat-treating is performed to form a platinum-cobalt-copper bulk structure, and

wherein the platinum-cobalt-copper bulk structure exhibits perpendicular magnetic anisotropy.