| 摘要 |
PROBLEM TO BE SOLVED: To reduce the coefft. of friction of a back layer, to reduce running load, to improve the running durability and to enable satisfactorily deal with even the reduction in thickness. SOLUTION: A magnetic layer is disposed on one principal face of a nonmagnetic substrate and a back layer satisfying a-b>=40nm [where (a) is a height at which cross-sectional area accounts for 20% of the entire cross-sectional area and (b) is a height at which cross-sectional area accounts for 80%] is formed on the other principal face. The substrate has <=6.0μm thickness and preferably satisfies c.d<3> >=2.0×10<5> [where (c) is the Young's modulus (kg/mm<2> ) of the substrate in the transverse direction and (d) is the thickness (μm)].
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