Stillwellite glass-ceramics with ferroelectric properties

The process of crystallization of LaBGeO5 and PrBGeO5 phases with stillwellite structure from the glassy state is studied. Exotherms on differential thermal analysis curves for lanthanum borogermanate glasses are interpretated by using the X-ray diffraction and the second harmonic generation method data. It is shown that acentric nuclei of the stillwellite phase are formed at the early stages of crystallization. There is not any metastable phase, prior to stillwellite precipitation. Glass-ceramic samples with high stillwellite content were synthesized, and their properties were measured and compared with the properties of a single crystal of LaBGeO5.