| 摘要 |
PURPOSE:To extremely reduce sliding noise and to improve the recording/ reproducing characteristics of a magnetic recording medium with high magnetic resistance by setting up the average crystal grain size of polycrystalline magnetic ferrite forming a magnetic core half to 5-30mu. CONSTITUTION:The magnetic core parts 1, 11 of the magnetic core halves I, II are constituted of polycrystalline ferrite, soft magnetic thin films 3, 13 are stuck to track width regulating grooves 2, 12 formed in the vicinity of abutting faces and the grooves 2, 12 filled with a non-magnetic material 22 to reduce the wear of the thin films 3, 13. The average grain size of the polycrystalline ferrite in the core parts is set up to 5-30mu. When the grain size exceeds the upper limit chippings or cracks may be easily generated, and when the grain size is dropped from the lower limit, the whole magnetic resistance is increased and effective magnetic permeability is reduced. Thereby, sliding noise is reduced, workability is improved and the electromagnetic conversion characteristics and wear resistance can be improved.
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