PHASE-TRANSITION IN PB5-XBAXGE3O11 (X=0.1, 0.2, 0.3)

Polycrystalline samples of modified lead germanate Pb5-xBaxGe3O11 (x = 0.1, 0.2, 0.3) have been prepared by a high-temperature solid-state r eaction method. Preliminary structural studies have been carried out u sing the X-ray diffraction technique. Measurements of dielectric permi ttivity (epsilon) and loss (tan delta) have been investigated, both as a function of frequency (10(2) to 10(4) Hz) and temperature (room tem perature to 190 degrees C). The phase transition temperature has been found to decrease at a rate of 18.8 degrees C per mol.% of substituted Ba2+. (C) 1998 Elsevier Science Ltd. All rights reserved.