Read-Write Characteristics of an NiFe/CoNiFe Laminated Thin-Film Head

The read-write characteristics of thin-film heads with a NiFe/CoNiFe laminated upper pole were studied. Compared with NiFe heads, NiFe/CoNiFe laminated heads are better able to suppress loss of output and increases in disk noise, and provide better overwrite characteristics. Comparison of experimental and calculated results indicate that pole saturation causes an increase in the transition length, because of the field gradient decrease, which results in an output decrease. The decrease in head efficiency due to the increase in the CoNiFe layer thickness is negligible if the latter is less than 20% of that of the upper pole. NiFe/CoNiFe laminated heads are deemed promising for high linear density recording.