Magnetic recording medium comprising a magnetic alloy layer of cobalt nickel, platinum and chromium formed directly on a nickel alloy amorphous underlayer

Abstract

A magnetic thin film alloy comprising cobalt, chromium, nickel and platinum for horizontal recording has a high coercivity, good corrosion resistance, and good noise performance. The platinum has a concentration between 8 to 15 atomic percent, the chromium has a concentration of 3 to 8%, the nickel concentration is 5 to 10% and the balance consist of essentially cobalt. The magnetic alloy has a thickness less than 100 nm and is sputtered on an undercoat consisting of nickel and phosphorus. The phosphorus content is between 5 to 30 weight percent, and the nickel phosphorus has a thickness between 5 and 100 nm. Alternatively, other amorphous metallic thin film undercoats can be applied. By judicious selection of the amount of chromium and nickel in the alloy, the saturation magnetization can be kept high while still maintaining good corrosion resistance. In addition, the sputtered media exhibits low noise.

Dependencies are inferred from the claim text.