Thickness Dependence of the Domain Width in Thin Crystals of BaFe₁₂O₁₉and SrFe₁₂O₁₉

Abstract

The domain structures on the (0001) plane of BaFe12O19 and SrFe12O19 have been studied by the Faraday effect and the Bitter figure technique. The samples of thin single crystals grown by Brixner's method were identified by X-ray analysis and magnetic measurement. The thickness dependence of the domain width was measured on the selected samples by the optical microscope. The results of both compounds in the thickness range from 2 to 25 µ are described by the following relations: D∝T2/3, or with equal probability by D2∝T-b, where D, T and b denote the width of the plate-like domain, the crystal thickness and a material constant respectively.