TWO-LAYERED GARNET FILM FOR MAGNETO-OPTICAL RECORDING MEDIUM AND MAGNETO-OPTICAL RECORDING DISK

摘要

PURPOSE: To ameliorate the disturbance of bit shapes and medium noise by forming two-layered films of polycrystalline garnet as represented by a prescribed compsn. ;CONSTITUTION: The polycrystalline film of the garnet is formed by a high-frequency sputtering method on a glass substrate and a second layer of the polycrystalline film of the garnet is similarly formed under the similar conditions thereon. Magnetic layers are formed by heat treating these films. Further, a Cr metal is sputtered as a reflection and heat absorption layer thereon under the similar conditions. The first garnet layer is the polycrystalline garnet having a Curie temp. below room temp. and the second garnet layer is the polycrystalline garnet having the Curie temp. above room temp. The compsns. thereof are expressed by formula BixR_3-x+uM_yFe_5-y+vO₁₂. In the formula, x: 0≤x≤3, y: 0≤y≤5, u:-3hu≤3, v:-5≤v≤5, R: i1 kinds of rare earth elements contg. yttrium, M: tervalent metal substitutable for iron. As a result, the disturbance of the pit shapes and the medium noise are ameliorated.;COPYRIGHT: (C)1994,JPO