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Spin Valve Head with Series Connected Current-Perpendicular-to-Plane Type Elements

IP.com Disclosure Number: IPCOM000118646D
Original Publication Date: 1997-Apr-01
Included in the Prior Art Database: 2005-Apr-01
Document File: 2 page(s) / 39K

Publishing Venue

IBM

Related People

Gill, HS: AUTHOR

Abstract

More sensitive heads are required as areal density increases. Current-In-Plane (CIP) type spin valve designs are expected to extend the areal density of the magnetic storage system to at least ten Gbit/in2. It may be necessary to enhance the head sensitivity as areal density increases further. Current-Perpendicular-to-Plane (CPP) is known provide about a factor of four improvement in magnetoresistive coefficient over CIP design. However, very low resistance of the CPP configuration is a major problem for the data storage head application.

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Spin Valve Head with Series Connected Current-Perpendicular-to-Plane
Type Elements

      More sensitive heads are required as areal density
increases.  Current-In-Plane (CIP) type spin valve designs are
expected to extend the areal density of the magnetic storage system
to at least  ten Gbit/in2.  It may be necessary to enhance the head
sensitivity as areal density increases further.
Current-Perpendicular-to-Plane (CPP) is known provide about a factor
of four improvement in magnetoresistive coefficient over CIP design.
However, very low resistance of the CPP configuration is a major
problem for the data storage head application.

      Series connected CPP spin valve elements are shown in the
Figure.  Each Free film is sandwiched between the "Cu" spacers which
are in turn sandwiched between the Pinned films.  This basic unit of
the Free film, two "Cu" spacers, and two Pinned films is then
repeated to achieve the desired resistance and magnetoresistance.
The Figure shows three basic units connected in series.  The total
resistance is nR, where n is the number of the basic units and R is
the resistance of one unit.  The number of units, i.e., the thickness
of the structure  and its height (dimensions perpendicular to current
flow) determines the number of squares and, therefore, the total
resistance of the sensor.  This scheme allows achieving the desired
resistance while maintaining high magnetoresistive coefficient (*).
  Reference
  (*) M.A.M. Gijs et al...