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Browse Prior Art Database

Improvement of Write Isolation in Tape Heads

IP.com Disclosure Number: IPCOM000108714D
Original Publication Date: 1992-Jun-01
Included in the Prior Art Database: 2005-Mar-22
Document File: 2 page(s) / 71K

Publishing Venue

IBM

Related People

Nix, JL: AUTHOR

Abstract

In tape subsystems such as 3480 which use a magnetoresistive (MR) sensor as the read element, we find that a source of feedthrough noise is caused by the coupling of write energy through the media to the magnetoresistive sensor. The path for this feedthrough noise is from the write coil to the head tape interface, through the tape, and then into the MR sensor which is in intimate contact with the tape asperities. Results will vary depending on the conductivity and surface characteristics of the tape media.

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Improvement of Write Isolation in Tape Heads

       In tape subsystems such as 3480 which use a
magnetoresistive (MR) sensor as the read element, we find that a
source of feedthrough noise is caused by the coupling of write energy
through the media to the magnetoresistive sensor.  The path for this
feedthrough noise is from the write coil to the head tape interface,
through the tape, and then into the MR sensor which is in intimate
contact with the tape asperities.  Results will vary depending on the
conductivity and surface characteristics of the tape media.

      The low impedance path of the write coil to the head surface
can be caused by impurities during fabrication. Further, there
generally exists a capacitive path from the coil to the head-tape
interface which provides a low impedance push above 100 kHz in
frequency.  These paths enter into the transmission of energy from
the write-to-read circuit.

      To solve this problem, we introduce a relatively thin band of
low resistivity metal at or near the head-tape interface which is
placed between the read and write elements to provide a
near-equipotential surface at the head-tape interface.  The metal
band is usually placed at ground potential by DC or AC coupling which
provides a low impedance shunt to short write energy to ground before
it reached the reader.  We form this low resistivity metal layer by
deposition on the substrate layers of the head to position the metal
band between the read and...