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Electrical Resistance Reduction in Metal Particle, Barium Ferrite and Cobalt-Iron Oxide Tapes by Using A1-Deposited Substrate

IP.com Disclosure Number: IPCOM000112870D
Original Publication Date: 1994-Jun-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 93K

Publishing Venue

IBM

Related People

Mathur, MCA: AUTHOR

Abstract

The magnetic recording tapes fabricating using the passivated iron (metal), Co-modified iron oxide or barium ferrite particles suffer from very high magnetic surface resistance as compared to the tapes made from using the Cr02 particles. This is because the intrinsic conductance of the metal, BaFeand cobalt-iron oxide particles is much higher than that of the Cr02 particles. The tapes with high surface resistance during the tape motion will generate static charge on the magnetic surface. The build up of the charge will either attract unwanted debris on the tape surface and will reduce the reliability of the tapes by increasing the head to tape distance or if the static charge is allowed to drain in undesirable or random directions, this will damage the head or tape or both during the read/write process.

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This is the abbreviated version, containing approximately 52% of the total text.

Electrical Resistance Reduction in Metal Particle, Barium Ferrite
and Cobalt-Iron Oxide Tapes by Using A1-Deposited Substrate

      The magnetic recording tapes fabricating using the passivated
iron (metal), Co-modified iron oxide or barium ferrite particles
suffer from very high magnetic surface resistance as compared to the
tapes made from using the Cr02 particles.  This is because the
intrinsic conductance of the metal, BaFeand cobalt-iron oxide
particles is much higher than that of the Cr02 particles.  The tapes
with high surface resistance during the tape motion will generate
static charge on the magnetic surface.  The build up of the charge
will either attract unwanted debris on the tape surface and will
reduce the reliability of the tapes by increasing the head to tape
distance or if the static charge is allowed to drain in undesirable
or random directions, this will damage the head or tape or both
during the read/write process.  Reduction magnetic surface resistance
to E5-E6 ohm/sq level is essential for the static charge reduction on
the tape's surface.

      Currently one of the following procedures are used to reduce
the magnetic surface resistance of the particulate tapes:

1.  Addition of the conducting materials (carbon or Ti0 etc.)  in the
    magnetic coating formulation.

2. Coating a conducting under layer under the magnetic layer.

3.  Putting a conducting layer as a back coat.

      The addition of non-magnetic material like carbon or Ti0 in the
magnetic layer (procedure #1) will reduce the loading of the magnetic
particle in the magnetic coating and therefore, will reduce the
signal amplitude of the tape which is bad.  Also, addition of the
material like carbon and Ti0 will complicate the formulation,
dispersion and rheology resulting in poor coating.  The procedures #2
and #3 will require additional and expensive coating steps and the
disposal of the organic solvents and other organic waste to expensive
waste disposal areas.  This will increase the product cost and is bad
for the environment.  The use of back coat to reduce the resistance
of the magnetic surface is a totally inefficient method because the
distance between the magnetic surface is long, and also an insulator
layer of the substrate exists between the magnetic surface and back
coat acting as a barrier for the charge drainage.

      The procedure discussed in this technical invention disclosure
eliminates all these problems and is efficient enough to bring the
magnetic surface resistance of the media to the desired level of
E5-E6 ohm, yet requires no additional coating...