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Magnetic Media for Backside Recording

IP.com Disclosure Number: IPCOM000047269D
Original Publication Date: 1983-Oct-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 3 page(s) / 107K

Publishing Venue

IBM

Related People

Chamberlin, TJ: AUTHOR [+3]

Abstract

Magnetic transitions recorded on a magnetic medium can be very broad, especially when the recording head is on the backside of the tape, as shown in Fig 1, where the non-magnetic substrate is holding the magnetic medium away from the highest magnetic field gradients produced by the magnetic head. In magnetic tapes where strong transitions and strong signals are desired, as in magnetic printing, a medium with a high magnetic material content is often used, which usually takes a high magnetic flux to saturate the medium. When the medium is spaced from the head as shown, the fields the magnetic head is able to produce may only partially record the layer of the medium. This condition, as seen from the front side of the tape, could prove unsatisfactory in terms of the transitions above the surface.

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Magnetic Media for Backside Recording

Magnetic transitions recorded on a magnetic medium can be very broad, especially when the recording head is on the backside of the tape, as shown in Fig 1, where the non-magnetic substrate is holding the magnetic medium away from the highest magnetic field gradients produced by the magnetic head. In magnetic tapes where strong transitions and strong signals are desired, as in magnetic printing, a medium with a high magnetic material content is often used, which usually takes a high magnetic flux to saturate the medium. When the medium is spaced from the head as shown, the fields the magnetic head is able to produce may only partially record the layer of the medium.

This condition, as seen from the front side of the tape, could prove unsatisfactory in terms of the transitions above the surface. In magnetic printing, the toner attractive force is proportional to the field and the field gradient. Backside recording for magnetic printing is desired to keep toner off the recording head. One way to boost the tape's recorded signal is to make the magnetized region squarer, (i.e., reduce transition length), as in Fig. 2. Here, two different kinds of media are bonded together. The lower tape coating has a higher coercivity, taking a greater strength of field to write, and the upper tape has lower coercivity with a lower recording field strength. If these two materials are selected with care, they can be matched to the distance from the head and the strength of the head field to produce squarer magnetized regions, resulting in stronger tape fields and sharper transitions on the top surface. This structure can also be used to vary the surface properties of the medium to desired values (i.e., roughness, conductivity, etc.) without substantially changing the bulk of the recording material.

The two-material media could be fabricated of a combination of the following materials: gamma ferrite oxide, chromium dioxide...