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Herringbone Pattern for Cylindrical Magnetic Domains

IP.com Disclosure Number: IPCOM000074295D
Original Publication Date: 1971-Apr-01
Included in the Prior Art Database: 2005-Feb-23
Document File: 2 page(s) / 38K

Publishing Venue

IBM

Related People

Keefe, GE: AUTHOR [+2]

Abstract

A conventional herringbone permalloy pattern for propagation of cylindrical magnetic domains uses an off-chip drive for the AC field. Since the AC field is varied over the entire magnetic chip, the bit rate is limited by the large inductance of the AC field coils. To overcome these limitations, a strip line is deposited on the permalloy herringbone pattern and on-chip drive is used for the AC field. Selection and access of a particular shift register channel is easier since currents can be directed in particular strip lines.

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Herringbone Pattern for Cylindrical Magnetic Domains

A conventional herringbone permalloy pattern for propagation of cylindrical magnetic domains uses an off-chip drive for the AC field. Since the AC field is varied over the entire magnetic chip, the bit rate is limited by the large inductance of the AC field coils. To overcome these limitations, a strip line is deposited on the permalloy herringbone pattern and on-chip drive is used for the AC field. Selection and access of a particular shift register channel is easier since currents can be directed in particular strip lines.

Figs. A and B show top and side views, respectively, of the modified herringbone structure. A magnetic chip 10, such as orthoferrite or garnet, is capable of supporting propagation of cylindrical magnetic domains 12 therein. Deposited on chip 10 is a conventional herringbone permalloy pattern 14. Deposited on the pattern 14 is a strip line 16, as for example, copper.

Propagation of domain 12 occurs when a DC magnetic field is applied in the plane of chip 10. This field is produced by off-chip drive coils, as is conventional in herringbone patterns. In contrast with the conventional patterns, the AC magnetic field in the plane of chip 10 is provided by bipolar current pulses along strip line 16. The AC field is orthogonal to the DC field, which is along the direction of the strip line. Travelling magnetic charge is, therefore, created along the corners 1, 2 of permalloy pattern 14.

The magni...