Structural, optical, electrical and dielectric properties of Bi_1·5Zn_0·92Nb_1·5−xNi_xO_6·92−3x/2 solid solution

Abstract

The effects of Ni content on the structural, optical, dielectric and electrical properties of Bi_1·5Zn_0·92Nb_1·5O_6·92 pyrochlore ceramics have been investigated. Nickel atoms were inserted into pure samples in accordance to the composition Bi_1·5Zn_0·92Nb_1·5−xNi_xO_6·92−3x/2, with x varying from 0·07 to 0·40. The structural analysis revealed that a single phase of the pyrochlore compound can be obtained for x values of 0·07 and 0·10 only. Further increase in Ni caused the appearance of multiple phases. The optical energy band gaps are determined as 3·30, 3·35 and 3·52 eV for Ni content of 0·00, 0·07 and 0·10 respectively. The temperature dependent electrical resistivity and the frequency dependent capacitance are observed to increase with increasing Ni content. The resonance frequency, which was determined from the capacitance–frequency dependence, was observed to shift from 12·14 to 10·47 kHz as the x values increase from 0·00 to 0·10 respectively.

Keywords:

• Pyrochlore
• Chemical synthesis
• X-ray scattering
• Optical properties
• Electrical properties

This work was supported by The Scientific and Technological Research Council of Turkey (TÜBİTAK) under grant no. 107M083. The authors would also like to thank the BSc student Mrs B. H. N. Kmail from the Department of Physics, Arab-American University, Palestine, for her help in the electrical data collection.