VISUALIZATION OF MAGNETIC DOMAIN-STRUCTURES THROUGH THE INTERACTION OF THEIR STRAY FIELDS WITH MAGNETOOPTIC GARNET-FILMS

A technique is described for the indirect visualisation of magnetic do main structures through the coupling of stray surface magnetic fields into a bismuth-substituted garnet layer. The resulting magnetisation d istribution within the garnet layer is visualised optically using the polar Kerr effect. A small single-crystal platelet of barium hexaferri te is used to demonstrate the method and the complex, field-induced ma gnetisation patterns in the garnet are discussed qualitatively. The ef fect of a small bias field on the magnetisation structures is also con sidered and has been shown to be a means of simplifying the complex im ages which are produced. This indirect magneto-optical method of visua lising magnetic domains is both effective and convenient, although the ultimate limits of resolution for the technique remain to be determin ed.