Western Digital Technologies, Inc.

Rong Cao

Ming Mao

Howard Gordon Zolla

Chen-jung Chien

Guanxiong Li

The present disclosure generally relates to a dual free layer (DFL) read head. In one embodiment, a dual free layer (DFL) read head, comprising: a tunnel magneto resistance (TMR) sensor disposed at a media facing surface (MFS); soft bias (SB) side shields disposed adjacent to the TMR sensor at the MFS; and a rear soft bias (RSB) disposed adjacent to the TMR sensor recessed from the MFS. The RSB has a nonmagnetic cap, the nonmagnetic cap comprising: a first nonmagnetic cap layer; and a second nonmagnetic cap layer, wherein an etch selectivity of the first nonmagnetic cap layer to the second nonmagnetic cap layer is a ratio of a:b in a first chemistry and a ratio of x:y in a second chemistry, wherein a is greater than b, and y is greater than x, and the second nonmagnetic cap layer is disposed on the first nonmagnetic cap layer.

Cap layer able to be reactive ion etched for RSB DFL read elements

A method of forming a magnetic head includes forming a read sensor stripe, depositing an electronic lapping guide (ELG) layer over the substrate in an ELG region, forming a backside edge of a read sensor by patterning the read sensor stripe in a first patterning step, forming a backside insulator layer and a rear bias magnetic material portion over the backside edge of the read sensor, forming a backside edge of an ELG by patterning the ELG layer in the ELG region in a second patterning step, simultaneously forming a front side edge of the read sensor and a front side edge of the ELG, and lapping the read sensor and the ELG to provide an air bearing surface of a read sensor. The physical stripe height offset can be determined for each flash field by correlating device conductance and ELG conductance.

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Fremont, CA, United States of America

Rong Cao