Transition Metal Ions and Heterogeneous Nucleation in Glass. Technical Report No. 3. Magnetic and Morphological Study of Fe2O3 Catalysed Crystallisation in a CaO-MgO-Al2O3-SiO2Glass.

摘要

A CaO-MgO-Al2O3-SiO2 glass containing the nucleating catalyst Fe2O3 was subject to a series of nucleating heat treatments. Magnetic susceptibility measurements from room temperature to 50mK have been made on these samples, and the paramagnetic resonance down to 4K determined. The morphology of the specimens was concomitantly investigated using SAXS (Small angle x ray scattering), optical microscopy and electron microscopy. All the magnetic measurements above 2K failed to reveal any changes upon nucleation heat treatments. Magnetic susceptibility measurements below 2K showed systematic variations in the magnetic behaviour with nucleation. The structural variations responsible were not determined. In conclusion, this study indicates that the mechanism of catalysed crystallisation in this glass is very subtle.