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Instant Bitter Technique for Defect Evaluation in Cylindrical Domain Processing

IP.com Disclosure Number: IPCOM000075468D
Original Publication Date: 1971-Sep-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 27K

Publishing Venue

IBM

Related People

Albert, PA: AUTHOR

Abstract

This is a process of evaluating the suitability of a crystal of magnetic domain material during the initial polishing steps, without removing the crystal from the polishing apparatus.

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Instant Bitter Technique for Defect Evaluation in Cylindrical Domain Processing

This is a process of evaluating the suitability of a crystal of magnetic domain material during the initial polishing steps, without removing the crystal from the polishing apparatus.

In ferrimagnetic cylindrical domain materials, the rest state of domain patterns comprise snake-like bands which are observable by transmitted light. When crystals are mounted for polishing, such examination is not possible without demounting the crystal from the holder required by the polishing operation.

The following technique does not require demounting of the crystal from the polishing holder yet will clearly outline the domain patterns in the crystal, as well as highlighting any defects in the crystal or in the domain walls. If during the polishing operation with a standard 6 micron diamond paste polishing wheel, after preparatory treatment with a #600 grit, the surface of a sheet 10 of magnetic domain material is diluted with water the domain boundaries 12, 13, 14, 15, 16 & 17 become clearly outlined by particles of magnetic material ground away by the wheel.

This outlining of the domains also reveals defects, not otherwise observable, which will hinder domain motion. Such a defect is shown by the straight line portion 18 of wall 13. When such defects are revealed, an early evaluation of them can be made to determine if further polishing or other treatment of the crystal is warranted. Such an earl...