Preparation of the alloy target for magneto-optical recording media

A novel method of preparing rare-earth-transition metal (RE-TM) alloy targets suitable for use as magnetooptical media is developed. Three different targets are studied. One contains only alloy powders made by simultaneous reduction of and diffusion reactions between RE-oxide and TM powders (target A). The others contain alloy powders combined with both RE powders (target B) and alloy powders combined with both RE and TM powders (target C). Radial distributions of the film compositions on the disks are observed. Compositional variance of sputtered films prepared by targets that underwent long usage is also monitored. The compositional uniformity in the radial direction is superior for targets B and C. Target A, which has the lowest permeability among the three, exhibits better aging behaviour