Patent ID: 8881378
Filing Date: 2014-11-11
Classification: B32B,G01R,Y10T

Abstract:
1. A method to improve performance of a magneto-resistive (MR) sensor under conditions of high areal density, comprising: forming, on a lower magnetic shield, a MR stack that further comprises a free layer on a tunneling barrier on a reference layer on an anti-parallel coupling layer on a pinned layer on an antiferromagnetic layer; providing a first pair of hard bias magnets that flank said MR stack; providing a second pair of hard bias magnets that flank said first pair of hard bias magnets; selectively removing a portion of said MR stack and of said first pair of hard bias magnets until said free layer, and optionally some of said tunneling barrier, are removed, thereby forming an area of reduced thickness that extends inwards from a back edge for a first distance; selectively covering said area of reduced thickness with a first layer of non magnetic insulation; forming, on said first layer of non magnetic insulation, a flux guide having a thickness and a top surface that is coplanar with a top surface of said free layer, said flux guide extending from said back edge to within a second distance from said free layer; depositing a second layer of non magnetic insulation on said flux guide; then depositing an upper magnetic shield on said second layer of non magnetic insulation thereby forming said MR sensor; and then exposing said MR sensor to an external magnetic field whereby said first pair of hard bias magnets provide a permanent stabilizing magnetic field for said free layer and said second pair of hard bias magnets provide a permanent stabilizing magnetic field for said flux guide.