Studies of Structural and Electrical Behavior of Samarium Barium Tungstate Ceramics

Abstract

Polycrystalline samples of samarium barium tungstate [ Sm2(Ba0.5W0.5)2O7 : (SBW)] pyrochlore structure type oxides have been prepared by a solid-state reaction technique. X-ray diffraction (XRD) patterns of this compound at room temperature suggest the formation of a single phase compound with orthorhombic structure. Studies of the dielectric constant and dielectric loss of compound as a function of frequency (4 kHz–1 MHz) at room temperature, and as a function of temperature (23–350°C) at 20 and 50 kHz frequencies suggest that the compound does not have dielectric anomaly. The variation of dc resistivity suggests the semiconductor characteristics of the material. The value of activation energy (E a ~ 0.43 at 20 kHz and E a ~ 0.29 at 50 kHz) of the above mentioned compound has been calculated from the slope of the ln σac versus 1/T graph in the high temperature region (> 240°C). The low value of activation energy supports the superionic nature of the compounds in the high temperature region.

Dielectric Relaxation in Complex Perovskite Oxide Sr(Gd<sub>0.5</sub>Nb<sub>0.5</sub>)O<sub>3</sub>

“…The dielectric study of lead-free ternary compounds has been the focus of researchers in recent years and some interesting results have already been reported [17][18][19][20][21]. Recently, our group has also studied the dielectric relaxation behavior of some A(B′B″)O 3 type perovskite oxides [22][23][24][25][26][27][28][29][30]. In this paper we investigate the structural and dielectric relaxation properties of the strontium gadolinium niobate, Sr-(Gd 0.5 Nb 0.5 )O 3 , (SGN) ceramics in the temperature range from 60˚C to 420˚C and in the frequency 50 Hz to 1 MHz by means of dielectric spectroscopy.…”