SYNTHESIS, STRUCTURAL AND ELECTRICAL CHARACTERIZATION OF Gd_2(Ba_(0.5)W_(0.5))_2O_7 CERAMICS

摘要

The polycrystalline sample of pyrochlore-type Gd_2 (Ba_(0.5)W_(0.5))_2O_7 (GBM) compound was synthesized by solid-state reaction technique. Preliminary, room temperature X-ray studies suggest the formation of single phase desired compound with cell parameters a = 11.691 (2) A, b= 7.023 (5) A and c = 13.864 (2) A in the orthorhombic crystal structure. SEM study with different magnifications provides information on quality of the sample and the uniform grain distribution over the entire surface of the sample. Detailed studies of the dielectric constant (t) and loss tangent (tan δ) of GBW as a function of frequency (0.1 kHz to 100 kHz) at mom temperature (23℃) and as a function of temperature (RT to 350℃) at different frequencies suggest that the compound do not have any dielectric anomaly in the studied frequency and temperature range. A c conductivity has been studied over a wide range of temperature. Variation of dc resistivity with electric field (0.5—50V/cm) at different temperatures and variation of dc resistivity with temperature (RT—370℃) at constant electric field of 60 V/cm showed the low-activation energy semiconductor characteristics of the material.