Magneto-optic microscope system for magnetic domain studies

Abstract

A Kerr magneto-optic microscope system provides efficient observation and recording of magnetic domains and their motions in soft magnetic materials and devices. Laser-source illuminators have allowed video recordings of domain motions to be taken through 20μm thick transparent covercoats even at the highest optical magnification. A basis for understanding the critical choices of system components and the adjustments necessary to produce low noise domain contrast is discussed. Examples of Kerr contrast photographs in simple permalloy elements are given. Most examples represent magnetic phenomena imaged previously by other techniques. However, some images presented here and elsewhere show details not previously seen by optical methods; they indicate a level of quality and resolution overlapping the capabilities of inherently higher resolution but less versatile methods.