| 摘要 |
PROBLEM TO BE SOLVED: To realize a high recording density by providing a difference in level shaped protrusion whose width is smaller than that of a third magnetic layer at the opposed part between a second magnetic layer an the third magnetic layer to make an erasing width small and also to make the shape of a magnetization transition area satisfactory. SOLUTION: The position of a protrusion 31 which is provided on a second magnetic layer is a part in which the second magnetic layer 30 is to be opposed to a third magnetic layer 12 across a gap film layer 11. Then, the width of the protrusion 31 is smaller than that of the third magnetic layer 12. Moreover, it is desirable that the difference between the width of the protrusion 31 and the width of the third magnetic layer 12 is not smaller than 0.05μm and is not larger than 0.8μm. When the difference between them is too small, it is sometimes generated that the opposed part between them is shifted and the erasing width in one side becomes large and when the difference between them becomes equal to or larger than 0.8μm, convergence of the magnetic flux becomes insufficient and then the erasing width is constant, however an overall magnetic field intensity is lowered.
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