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Increased Resolution of Magnetic Bubble Domains in Optically Transparent Films by a Fraunhofer Diffraction Technique

IP.com Disclosure Number: IPCOM000079529D
Original Publication Date: 1973-Jul-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 2 page(s) / 25K

Publishing Venue

IBM

Related People

Matthews, JW: AUTHOR [+2]

Abstract

A system is provided for detecting magnetic bubbles in a transparent carrier, wherein the bubbles have diameters as small as 0.05 to 0.5 microns.

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Increased Resolution of Magnetic Bubble Domains in Optically Transparent Films by a Fraunhofer Diffraction Technique

A system is provided for detecting magnetic bubbles in a transparent carrier, wherein the bubbles have diameters as small as 0.05 to 0.5 microns.

The system is shown schematically in the figure and comprises a polarized source of light 2, a transparent support 4 capable of carrying magnetic bubble domains therein, an analyzer 6, a wide-aperture lens 8, and a screen or suitable detector 10. Representative bubble supporting materials are the rare earth orthoferrites and garnets. The magnetized garnets form bubbles of the order of
0.05 to 0.5 microns in diameter. Due to the Faraday effect, such bubbles act as phase gratings so that by proper orientation of the analyzer, Fraunhofer diffraction patterns are obtained on the screen which correspond to the Fourier Transform of the bubble distribution.

The above-noted patterns which, for circular bubbles, consist of one or two concentric rings, constitute the shape transform of an "average" bubble, and correspond to the diffraction pattern of a circular opening in standard diffraction theory. From these diffraction rings, the bubble size can be directly inferred from standard diffraction ring analysis. Greater resolution is achievable by using shorter wavelengths of light for the source 2, namely, ultraviolet.

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