Operational Method for Locating and Mapping Imperfections in Single-Crystal Platelets of Rare-Earth Orthoferrite

Abstract

An instrumental technique has been devised for mapping crystalline imperfections which prevent the reliable operation of bubble‐domain devices. A special polarizing microscope permits the crystal to be automatically scanned through the field of view in a raster‐like manner. Photoelectrically detected distortions induced in a test domain by imperfections are plotted on an x‐y output of the scan. This sensitive method easily locates imperfections found with difficulty by other methods and has been used to locate crystals which have later been used successfully in devices.