| 摘要 |
PURPOSE:To obtain a permanent magnet thin film having high coercive force which will be used for a magnetic recording medium and a thin film magnetic device by a method wherein Co-Ir alloy containing specific quantity of Ir is used. CONSTITUTION:The coercive force 1 of the Co-Ir alloy thin film formed on a glass substrate by performing a sputtering is extremely low at approximately 30Oe on pure Co, but after the maximum value of approximately 550Oe has been attained on 15% Ur alloy, the coersive force is decreased as the quantity of Ir is increased, and the low coercive force of approximately 300Oe on a 25% Ir alloy and that of same as the pure Co on 40% Ir alloy or less can be obtained. On the other hand, the residual magnetic flux density of the Co-Ir alloy thin film is reduced almost rectilinearly as the quantity of Ir increases. When the above thin film permanent magnet is applied to a magnetic recording medium and a thin film magnetic device, it is desirable that it has the coercive force of 300Oe and the residual magnetic flux density of 2,500G or above. Accordingly, the range of Ir content of the Co-Ir alloy satisfies characteristic condition and a thin film permanent magnet is 7.5-25%, and the Co-Ir alloy thin film within the above-mentioned range of composition can be put to practical use as a permanent magnet thin film. |
