| 摘要 |
PROBLEM TO BE SOLVED: To decrease an antimagnetic field to fix the magnetization direction of a fixed layer and to obtain a high reproducing output with high recording density even with low magnetoresistance, by aligning the magnetization direction of a ferrimagnetic layer and the magnetization direction of the fixed layer opposite to each other to produce exchange coupling. SOLUTION: A ferrimagnetic layer 20 comprising a TbCo alloy or the like and a fixing layer 17 comprising TM atoms such as Co are laminated to produce exchange coupling of the magnetization 21 of the fixing layer 17 and the magnetic moment 24 of the TM atoms in the ferrimagnetic layer 20 so that the magnetization direction of the fixed layer 17 is opposite to the magnetization direction of the ferrimagnetic layer 20. The magnetostatic field 26 leaking from the edges of the fixing layer 17 is absorbed by the ferrimagnetic layer 20 to produce an antimagnetic field and eliminates gradient in the magnetization of the fixed layer 17 to make the magnetization direction uniform. Thereby, even when the magnetoresistance MR is low, decrease in the magnetoresistive changeΔR in the spin valve layer can be decreased. By controlling the compsn. and film thickness of the ferrimagnetic layer 20 to obtain an almost same magnetization-film thickness product as that of the fixed layer 17, the exchange coupling can be enough produced to increase its effect.
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