| 摘要 |
PROBLEM TO BE SOLVED: To provide a magneto-optical disk that can retain stable revolution and data reliability even in a high velocity revolution, has a central hole and revolves by way of a hub supported on the central hole. SOLUTION: The magneto-optical disk has at least a plastic substrate 1 having a central hole, layers including a recording layer consisting essentially of rare earth metals and transition metals laminated on the substrate 1 and a hub 3 supported on the central hole in the substrate 1 and comprising a material different from the material of the substrate 1. The disk is housed in a cartridge case in such a way that it can revolve, the housed disk is attached to the spindle 2 of a recording and reproducing device and recording or reproduction is carried out under revolution. A material having >=0.05 cal/ deg.C. cm.s heat conductivity is used for the hub 3, a material having >=5 kgf.cm/cm Izod strength is used for the substrate 1 and the relation of Y/X>=0.02 is satisfied between the contact area Y of the substrate 1 and the hub 3 and the projected area X of the substrate 1.
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