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Canted Contiguous Hard Bias Stabilization for Very Thin Magnetoresistive/Giant Magneto-Resistance Sensor

IP.com Disclosure Number: IPCOM000117806D
Original Publication Date: 1996-Jun-01
Included in the Prior Art Database: 2005-Mar-31
Document File: 2 page(s) / 46K

Publishing Venue

IBM

Related People

Gill, HS: AUTHOR

Abstract

The Magnetoresistive (MR) sensor thickness is decreasing to improve readback signal in response to increasing bit density. The thickness of the track edge hard bias material should be scaled with the sensor thickness to avoid sensor magnetic stiffness. In general, the magnetic thickness of the sensor and of the hard bias material are matched to achieve adequate magnetic stability and readback sensitivity. The MR, Giant Magneto-Resistance (GMR) and SPIN VALVE sensors for future high recording density are expected to be very thin, near 50 A or less. For hard bias materials with magnetization close to NiFe sensor, the thickness of the track edge bias films will also be near 50 A. Since these films are thin, the non-planar track edge junctions will lead to incomplete step coverage and insufficient track edge biasing.

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Canted Contiguous Hard Bias Stabilization for Very Thin Magnetoresistive/Giant
Magneto-Resistance Sensor

      The Magnetoresistive (MR) sensor thickness is decreasing to
improve readback signal in response to increasing bit density.  The
thickness of the track edge hard bias material should be scaled with
the sensor thickness to avoid sensor magnetic stiffness.  In general,
the magnetic thickness of the sensor and of the hard bias material
are matched to  achieve adequate magnetic stability and readback
sensitivity.  The MR, Giant Magneto-Resistance (GMR) and SPIN VALVE
sensors for future high recording density are expected to be very
thin, near 50 A or less.  For hard bias materials with magnetization
close to NiFe sensor, the thickness of the track edge bias films will
also be near 50 A.  Since these films are thin, the non-planar track
edge junctions will lead to incomplete step coverage and insufficient
track edge biasing.

      This problem could be overcome by using very thick (>200A) hard
bias film with magnetization canted away from the horizontal axis as
shown in Fig. 1(a).  Therefore, e.g., with canting angle of 75
degree, the horizontal component of magnetization which provides the
longitudinal bias is only (Mr x Cos 75), where Mr is remnant
magnetization of the hard bias material.  Therefore, proper hard bias
material thickness and canting angle of its magnetizations ensures
adequate step coverage and longitudinal bias which eliminates the
need...