| 摘要 |
PURPOSE:To write and erase with a low energy light by a method wherein an amorphous Tb-Eu-Fe ternary alloy thin film which has the easy-to-magnetize axis along the direction perpendicular to the film surface is introduced and the ratio of the member of atoms of Tb and Eu combined is limited within a specific range. CONSTITUTION:An amorphous Tb-Eu-Fe ternary alloy thin film which has the easy-to-magnetize axis along the direction perpendicular to the film surface is introduced and the ratio of the number of atoms of Tb and Eu combined is limited within the range of 15-40atomic%. In order to obtain magnetiz anisotropy which is enough to make the diction of the magnetization perpendicular to the film surface, an amorphous thin film of the thickness not less than several humdreds Angstrom is formed on a substrate which is maintained at the temperature not higher than the room temperature by sputtering, vacuum evaporation or the like. By limiting the composition of Tb and Eu within the specific range, Curie point of the amorphous thin film is 120-150 deg.C and its coercive force is 800- 3,000 oersted. With this constitution, the recorded information can be written or erased with a low energy light and the structural change caused by the heat is not produced. |
