Comprehensive study of crystallization and phase formation in (La,Gd)BGeO5 glass

Abstract

The glasses with (25-x) La2O3·xGd2O 3·25B2O3·50GeO2 composition corresponding to the (La,Gd)BGeO5 were prepared, and the substitution effect of gadolinium ions (Gd3+) on crystallization behavior and phase formation was examined by DTA, XRD and Raman techniques in detail. Ferroelectric (La,Gd)BGeO5 phase with hexagonal stillwellite structure were crystallized in the composition range of x = 0-15. Although no significant change in physical properties was observed in the whole composition range, crystallization behavior was drastically changed as the progressive substitution of Gd3+ was carried out (i.e., crystallization of monoclinic phase of (La,Gd)BGeO5 and high-pressure phase of Gd 2Ge2O7 with a triclinic structure). Structure of the glasses and crystallized phases, and the phase formation mechanism were also discussed. © 2008 The Ceramic Society of Japan. All rights reserved.