SPUTTERING TARGET FOR FORMING MAGNETO-OPTICAL RECORDING MEDIUM FILM AND ITS PRODUCTION

摘要

PROBLEM TO BE SOLVED: To provide a target for forming a magneto-optical recording medium film having a uniform concentration of rare earth elements by sputtering and its production. SOLUTION: This target consists essentially of the rare earth elements and is formed by integrally sintering and joining sintered annular targets varying in rare earth element contents to a concentric form so as to form a concentration gradient to increase the rare earth element contents in a radial direction from the center. The adjacently joined parts of the sintered annular targets are composed of the sintered compacts essentially consisting of the rare earth elements having the intermediate content compositions of the rare earth element contents of the sintered annular targets adjacent to each other. The difference between the rare earth element content in the outermost peripheral part of the target concentrically sintered and joined with the annular targets and the rare earth element content in the central part is within a range of 0.3 to 1.5 atm.%.