US 2006/0132988 A1 · Novel hard bias design for sensor applications

Abstract

A hard bias structure for biasing a free layer in a MR element within a magnetic read head is comprised of a soft magnetic underlayer such as NiFe and a hard bias layer comprised of Co78.6Cr5.2Pt16.2 or Co65Cr15Pt20 that are rigidly exchange coupled to ensure a well aligned longitudinal biasing direction with minimal dispersions. The hard bias structure is formed on a BCC seed layer such as CrTi to improve lattice matching. The hard bias structure may be laminated in which each of the underlayers and hard bias layers has a thickness that is adjusted to optimize the total HC, Mrt, and S values. The present invention encompasses CIP and CPP spin values, MTJ devices, and multi-layer sensors. A larger process window for fabricating the hard bias structure is realized and lower asymmetry output and NBLW reject rates during a read operation are achieved.

Claims20

Dependent claims

A method of forming a hard bias structure in a magnetic read head based on an MR element, comprising:

(a) providing a substrate on which an MR element having a top surface and two sides and that is comprised of a free layer which has two sidewalls coincident with said sides is formed;
(b) forming a seed layer on said substrate and adjacent to a portion of each side of said MR element;
and
(c) forming a hard bias structure on the seed layer wherein the hard bias structure is comprised of:
(1) a soft magnetic underlayer;
and
(2) a hard bias layer that forms an abutting junction with the free layer on each side of the MR element;
said hard bias layer is rigidly exchange coupled with the soft magnetic underlayer and thereby provides optimum HC and Mrt values to ensure a well aligned biasing direction to minimize dispersions at the abutting junctions.

5 more elements

Dependencies are inferred from the claim text.

Novel hard bias design for sensor applications

Life of this patent

Novel hard bias design for sensor applications

Life of this patent

Abstract

Claims20