Applying amorphous CoNbZr shield to improve the dielectric-breakdown voltage of the gap layers of narrow-gap read heads

We investigated the dependence of the dielectric-breakdown voltage of the gap layer on lower shield material. The dielectric breakdown voltage of the gap layer is higher for the test elements with the CoNbZr shield than that with the NiFe shield, especially in the thin-gap range. The dielectric-breakdown voltage is about twice as high with the CoNbZr shield as with the NiFe shield for a 20-nm-thick gap layer. We also investigated the dielectric breakdown of the gap layer and the head performance using the CoNbZr-NiFe hybrid lower shield. The hybrid-shield head showed higher dielectric breakdown than that of the conventional NiFe shield. In terms of read performance, there is no difference between hybrid and conventional shield heads. The shield-to-shield spacing can decrease to 65 nm by using a hybrid shield. The hybrid shield is much more efficient in narrow-gap read heads than conventional shields.