Browse Prior Art Database

Low-Noise Planar-Inductive Film Head

IP.com Disclosure Number: IPCOM000106474D
Original Publication Date: 1993-Nov-01
Included in the Prior Art Database: 2005-Mar-21
Document File: 2 page(s) / 72K

Publishing Venue

IBM

Related People

Fontana, RE: AUTHOR [+4]

Abstract

Conventional inductive film heads used in longitudinal recording are made with planar pancake coils fabricated around nonplanar magnetic films. Disadvantages of the conventional design for longitudinal recording are that: 1) the ultimate read sensitivity and frequency response are limited by the high inductance per turn of the pancake coils, 2) the maximum write field is gated by the saturation of regions away from the pole tips so that the ability of the head to write on media with high coercivity is reduced, and 3) read back distortion can arise from magnetic domains that are difficult to control in the nonplanar magnetic films.

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Low-Noise Planar-Inductive Film Head

      Conventional inductive film heads used in longitudinal
recording are made with planar pancake coils fabricated around
nonplanar magnetic films.  Disadvantages of the conventional design
for longitudinal recording are that: 1) the ultimate read sensitivity
and frequency response are limited by the high inductance per turn of
the pancake coils, 2) the maximum write field is gated by the
saturation of regions away from the pole tips so that the ability of
the head to write on media with high coercivity is reduced, and 3)
read back distortion can arise from magnetic domains that are
difficult to control in the nonplanar magnetic films.

      The first limitation of a conventional film head can be reduced
with a planar head that is made from helical coils fabricated around
a planar magnetic film.  The second limitation can be addressed by
building a planar head on the side of the slider where the film
thickness determines the recording track width.  However, these
planar heads can still have problems associated with magnetic domains
as in the conventional heads.  This disclosure addresses the third
limitation by showing how to fabricate the magnetic films in a planar
head geometry so as to have the desired magnetic domain configuration
with low noise characteristics.

      The planar head yoke should be built in a square or rectangular
shape, as shown in Figs. 1 and 2.  This allows the fabrication of
each leg of the y...