Amorphous magnetic thin film and plane magnetic element using same

An amorphous magnetic thin film possessing a composition substantially represented by the chemical formula

• (Fe.sub.1-x CO.sub.x).sub.1-y (B.sub.1-z X.sub.z).sub.y
• wherein X stands for at least one element selected from the group consisting of the Group 4B elements in the CAS version of the Periodic Table and x, y, and z stand for numerals satisfying the expressions, 0.1.ltoreq.x.ltoreq.0.5, 0.06<y<0.5, and 0<z<1, said amorphous magnetic thin film possessing as at least part of a thin film forming area a microstructure composed of a first amorphous phase containing both iron and cobalt and bearing magnetism and a second amorphous phase disposed round said first amorphous phase and containing boron and at least one element selected from the group consisting of the Group 4B elements in the CAS version of the Periodic Table, and said second amorphous phase separating said first amorphous phase has an average thickness of not more than 3 nm.

A plane magnetic element, comprising a plane coil and an amorphous magnetic thin film disposed as superposed on at least one of opposite surfaces of said plane coil, said amorphous magnetic thin film containing iron, cobalt, boron and at least one element selected from the group consisting of the Group 4B elements in the CAS version of the Periodic Table, and possessing as at least part of a thin film forming area a microstructure composed of a first amorphous phase containing iron and cobalt and bearing magnetism and a second amorphous phase disposed round said first amorphous phase and containing boron and at least one element selected from the group consisting of the Group 4B elements, wherein said amorphous magnetic thin film exhibits uniaxial magnetic anisotropy in the plane of film, and said iron is of a greater amount than said cobalt.

An amorphous magnetic thin film possessing a composition substantially represented by the chemical formula

• (Fe.sub.1-x Co.sub.x).sub.1-y (B.sub.1-z X.sub.z).sub.y
• wherein X stands for at least one element selected from the group consisting of the Group 4B elements in the CAS version of the Periodic Table and x, y, and z stand for numerals satisfying the expressions, 0.1.ltoreq.x.ltoreq.0.5, 0.06<y<0.5, and 0<z<1,
• said amorphous magnetic thin film possessing as at least part of a thin film forming area a microstructure composed of a first amorphous phase containing both iron and cobalt and bearing magnetism and a second amorphous phase disposed round said first amorphous phase and containing boron and at least one element selected from the group consisting of the Group 4B elements in the CAS version of the Periodic Table, and an average thickness of said second amorphous phase separating said first amorphous phase is not more than 3 nm, said amorphous magnetic thin film exhibiting uniaxial magnetic anisotropy in the plane of film, said uniaxial magnetic anisotropy being induced by heat-treating at a temperature of not more than the Curie temperature of the amorphous magnetic thin film in a magnetic field, and said Curie temperature being not less than the crystallization temperature of the amorphous magnetic thin film.