An improved thin film permanent magnet material and novel magnetdesign for magnetoresistive sensor biasing
Smith, N.; Brucker, C.F.; Spada, F.E.
Magnetics, IEEE Transactions on
Volume 26, Issue 5, Sep 1990 Page(s):2409 - 2411
Digital Object Identifier 10.1109/20.104747
Summary:A high-performance CoPt thin-film permanent-magnet material and a
magnet design have been developed to provide an integrated bias field
source for unshielded magnetoresistive (MR) reproduce heads. A
1-μm-thick deposited permanent magnet is located above the MR element
and away from the media; it is fully encapsulated and removed from the
head/media interface. Problems of mutual demagnetization between magnet
and media, galvanic corrosion at the exposed MR and magnet edges, and MR
film degradation from an inhomogeneous adjacent permanent-magnet layer
are eliminated. A CoPt magnet of specific geometry is designed to
produce hard and easy axis bias fields, providing good single-domain
stability while maintaining high MR sensitivity. The CoPt sputter
deposition is a room-temperature process which is compatible with other
temperature-sensitive head materials
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