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Nondestructive Readout Magnetic Element

IP.com Disclosure Number: IPCOM000096794D
Original Publication Date: 1963-Nov-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 53K

Publishing Venue

IBM

Related People

Speliotis, DE: AUTHOR [+2]

Abstract

Segmenting allows a two layer nondestructive readout magnetic film element to be arranged about a cylindrical substrate. The spaces between segments provide necessary air gaps through which the dispersion field of high coercive force data films can control the magnetization of adjacent low coercive force readout films.

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Nondestructive Readout Magnetic Element

Segmenting allows a two layer nondestructive readout magnetic film element to be arranged about a cylindrical substrate. The spaces between segments provide necessary air gaps through which the dispersion field of high coercive force data films can control the magnetization of adjacent low coercive force readout films.

In each segment, the data film is magnetized in a given data direction as shown. Its dispersion field passes through its adjacent readout film and magnetizes the readout film in the opposite direction (dashed arrow) to complete a flux path. Readout is accomplished by driving the element with sufficient magnetic force to drive the readout film to a reference direction (dotted arrow) but insufficient to alter the state of the data film, sensing any magnetic flux change. After readout, the overpowering dispersion field of the data film returns the readout film to the pre readout state.

A complete cylinder or non segmented configuration of the data film is undesirable. It would provide a closed flux path (dashed circle), virtually eliminating the outside dispersion field of the data film required to control the readout film.

The element is formed by depositing, on cylindrical substrate, two complete layers and of magnetic material. This has suitable high low coercivity ratio and chemically etched away portions corresponding to the slots between segments. As an alternative, the slots can be scratched or cut. The e...