| 摘要 |
PROBLEM TO BE SOLVED: To decrease cupping and to improve head-touch property, recording and reproducing characteristics and durability by forming two magnetic films on a supporting body in such a manner that each film has a specified range of fluctuation of thickness and the sum thickness of the two films is almost constant. SOLUTION: A lower magnetic film 21 and an upper magnetic film 22 are formed on a supporting body 1. Each magnetic film shows fluctuation in the thickness but the sum thickness of the two films is controlled to almost constant. The changing rate of the thickness of the magnetic film ((max. thickness of the film-min. thickness)/max. thickness×100) is 8 to 40%, and especially 12 to 30% is preferable. If the changing rate is too large, fluctuation is caused in the output. By controlling the period of the fluctuation in thickness to smaller than 5 to 2000 times as the tape width, cupping can be prevented. The magnetic film is formed to 600 to 5000∼r thickness. By this constitution. stress concentration in the magnetic film can be decreased, which decreases cupping, improves the head-touch property, recording and reproducing characteristics and durability.
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