| 摘要 |
PROBLEM TO BE SOLVED: To increase S/N and output in a high range and to decrease the error rate by forming a lower magnetic film and an upper magnetic film on a supporting body in such a manner that the upper magnetic film is made thicker than the lower magnetic film. SOLUTION: A lower magnetic film 21 and an upper magnetic film 22 are formed on a base body 1 in such a manner that the upper magnetic film 22 is 1.1 to 3 times as thick as the lower magnetic film 21. The upper magnetic film 22 is formed to 600 to 2200Å, while the lower magnetic film 21 is formed to 200 to 2000Åto obtain 800 to 4200Åsum thickness. Further, the thickness of the upper magnetic film 22 is controlled to 1/6 to 1/4 of the recording wavelength. Bs of the lower magnetic film 21 is controlled to 4000 to 8000G, while Bs in the upper magnetic film 22 is controlled large as 5000 to 10000G. Then. a protective film 3 is formed on the upper magnetic film 22 and a lubricant layer 4 is formed thereon. Thereby, when the medium is used for 15MHz or higher main recording wavelength, the S/N and output in a high range can be improved and the error rate can be decreased.
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