| 摘要 |
PURPOSE:To prevent the crushing of a head and the stripping, breaking and other trouble of a ferromagnetic layer of Co-Cr or the like by forming a boron nitride-base protective film on the ferromagnetic layer. CONSTITUTION:A magnetic recording medium 1 such as a magnetic disk obtd. by forming a ferromagnetic layer such as a vertically magnetizable film of Co-Cr on a nonmagnetic substrate by a sputtering method is placed on an electrode 3 in a vacuum vessel 2. While heating the medium 1 with a heater 4, gaseous H2 in a cylinder 5 is introduced into the vessel 2, and gaseous B2H6 in a cylinder 6 and gaseous NH3 in a cylinder 7 are mixed through a mixer 8 and introduced into the vessel 2 from holes 10 pierced in an electrode 9. High frequency is then applied between the electrodes 3, 9 from an RF power source 11 to cause plasma discharge, and by the discharge a protective film of boron nitride BNx is formed on the medium 1. The preferred value of x is 0.5-1.5. |
