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Dual Gap Length Magnetic Heads

IP.com Disclosure Number: IPCOM000080898D
Original Publication Date: 1974-Mar-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 2 page(s) / 29K

Publishing Venue

IBM

Related People

Faircloth, CL: AUTHOR

Abstract

The single ring magnetic heads in Figs. 1 and 2 have a relatively short gap length during playback to provide high-resolution reading. During recording or erasing the heads have a longer gap length, to allow the flux to more readily penetrate the oxide thickness of a recording media to provide a well defined flux change.

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Dual Gap Length Magnetic Heads

The single ring magnetic heads in Figs. 1 and 2 have a relatively short gap length during playback to provide high-resolution reading. During recording or erasing the heads have a longer gap length, to allow the flux to more readily penetrate the oxide thickness of a recording media to provide a well defined flux change.

Magnetic heads 10 and 20 in Figs. 1 and 2 include read/record windings 3 and 4, respectively. Spacers 5 and 6 of lengths L1 and L3, respectively, are made of a nonmagnetic material.

Head 10 includes spacer 7 of length L2, interposed between spacer 5 and core 1. Spacer 7 has a saturation flux density substantially lower than that of core 1 but has a comparable permeability. With a relatively high-recording flux in core 1, spacer 7 saturates so that the effective gap length is L2. During the relatively low-flux levels of playback, however, spacer 7 does not saturate, and the gap length is L1. Spacer 7 is deposited on core 1 by electroplating or sputtering to eliminate an air gap at the junction of spacer 7 and core 1 that would, otherwise, give a low-amplitude playback signal preceding the desired playback signal.

Step 8 is formed on core 2 of head 20 of length L4 - L3 and height H1, by punching, etching, or grinding. When the relatively high-recording flux funnels from the relatively large gap surface of height H2 into the smaller gap surface of height H1, step 8 saturates and provides an effective record gap length...