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Orthogonal Spin Valve Sensor Stabilized by CoSm Hard Bias Film

IP.com Disclosure Number: IPCOM000118158D
Original Publication Date: 1996-Oct-01
Included in the Prior Art Database: 2005-Apr-01
Document File: 2 page(s) / 42K

Publishing Venue

IBM

Related People

Gill, HS: AUTHOR [+2]

Abstract

Orthogonal spin valve sensor, a sensor in which the sense current flows perpendicular to the air bearing surface, is attractive for high areal density data storage. The Hard Bias layers are placed at each track edge (Figure) to provide magnetic bias to achieve Barkhausen noise-free operation. The Hard Bias layers form contiguous junctions with the active spin valve sensor. As shown in the Figure, since the Hard Bias layers are electrically in contact with the sensor and form a parallel electrical circuit, a fraction of the sense current is shunted through the Hard Bias layers. Using sensor width of 2 um with sheet resistance of 15 Ohm/sq together with CoPtCr Hard Bias layers of width 1 um at each track edge and sheet resistance of 75 Ohm/sq yield about 20% sense current shunt loss through the Hard Bias layers.

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Orthogonal Spin Valve Sensor Stabilized by CoSm Hard Bias Film

      Orthogonal spin valve sensor, a sensor in which the sense
current flows perpendicular to the air bearing surface, is attractive
for high areal density data storage.  The Hard Bias layers are placed
at each track edge (Figure) to provide magnetic bias to achieve
Barkhausen noise-free operation.  The Hard Bias layers form
contiguous junctions with the active spin valve sensor.  As shown in
the Figure, since the Hard Bias layers are electrically in contact
with the sensor and form a parallel electrical circuit, a fraction of
the sense current is shunted through the Hard Bias layers.  Using
sensor width of 2 um with sheet resistance of 15 Ohm/sq together with
CoPtCr Hard Bias layers of width 1 um at each track edge and sheet
resistance of 75 Ohm/sq yield about 20% sense current shunt loss
through the Hard Bias layers.

      CoSm amorphous alloy film has been shown to exhibit electrical
resistivity above 200 uOhmCm, magnetization about 800 emu/cc, and
coercivity above about 500 Oe.  These properties are suitable for
Hard Bias application.  Using CoSm with sheet resistance of 250
Ohm/sq, reduces the sense current shunt loss through the Hard Bias
down to only  5 percent.  Use of CoSm Hard Bias for Orthogonal
sensor, therefore, improves the read sensitivity of the sensor.