| 摘要 |
PURPOSE:To enable efficient taking-out of light reproduction output by laminating respectively specific ternary amorphous magnetic alloy layers on a substrate. CONSTITUTION:The 1st ternary amorphous magnetic alloy layer 2 which satisfies the general formula I and is 0.15<=X<=0.2, 0<y<0.5 is provided on the substrate 1 in such a manner that the axis of easy magnetization is perpendicular to the film plane. The 2nd ternary amorphous magnetic alloy layer 3 which satisfies the general formula I and is 0.2<X<=0.35, 0<=y<0.5 is laminated on the layer 2 in such a manner that the axis of easy magnetization is perpendicular to the film plane. Light enters the medium from the layer 2 side. A large signal level is obtd. by this exchange junction constitution of the layer 2 in which the magnetization of FeCO sub-lattice is dominant and the layer 3 in which the magnetization of Dy sub-lattice is dominant. In addition, an increase in noise level is suppressed and writing energy can be diminished. Furthermore, the quantity of Dy decreases and the quantity of Co increases in the light incident face so that the film of the largest Kerr rotating angle exists therein. The reproduction level is thereby increased and the reproduction noises are decreased. The high-efficiency light reproduction output is thus taken out.
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