Magnetic force microscopy investigation of the domain structure of nanocomposite Nd2Fe14B/Fe3B magnets

In this paper, a detailed magnetic force microscopy study has been made of the domain structure of isotropic nanocomposite Nd2Fe14B/Fe3B magnet ribbons prepared by melt-spinning. The domain structure is composed of interaction domains a few hundred nanometers in size, which indicates the presence of a strong exchange coupling between the grains. Within the interaction domains, a fine substructure on the same scale as the grain size is observed with high-contrast and clarity, which is an improvement over earlier results. As a consequence, the interaction domains are clusters of many single-domain grains whose magnetization directions are not precisely the same but differ slightly. In general, the interaction domains have both perpendicular and in-plane magnetization components. The domain width of the interaction domains (260 +/- 20) nm was determined by digital means (using the method of Bodenberger and Hubert), in contrast to previous investigations. (C) 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.