Write performance of heads with a 2.1-Tesla CoNiFe pole

We examined the write performance of heads with a CoNiFe/NiFe composite write pole. The saturation induction B/sub s/ of the CoNiFe film was 2.1 T (21 kG). The CoNiFe layer thickness was typically 0.5-0.6 /spl mu/m, and the rest of the write pole was composed of Ni/sub 80/Fe/sub 20/. The dual high B/sub s/ layer structure with the CoNiFe films on both sides of the write gap gave excellent overwrite performance. It was over 30 dB for a medium that had a high coercivity of 560 kA/m (7.0 kOe).