Semi-Conduction and Electron Hopping in Vitreous Systems: Magnetic Properties, Micro-Structure, and Ultra-Structure of Partially Crystallised B203-BaO-Fe203 Glass

摘要

The crystallisation products and morphology of a 68B2O3 - 17 BaO - 15 Fe2O3 mole % glass have been studied using magnetisation measurements, small angle x-ray scattering measurements and replica electron microscopy. The glasses containing the crystallised phases were super-paramagnetic down to 77 degrees K, and the magnetisation curves are analysed in terms of a bimodal distribution of magnetic moments. The SAXS and electron micrographs confirmed the bimodal distribution of particle sizes, and a very precise correlation between magnetic properties and microstructure is obtained. By quantitative calculations, it is shown that the precipitate phases themselves are complex in structure, and most likely consist of an inner ferrimagnetic core surrounded by an anti-ferromagnetic grape-fruit skin. This structure for the precipitates is confirmed directly by electron microscope observations. (Author)