High temperature impedance spectroscopy study of non-stoichiometric bismuth zinc niobate pyrochlore.

• Main Authors: Tan, Kar Ban, Khaw, C. C., Lee, C. K., Zainal, Z., Tan, Y. P., Shaari, Hasnizam
• Format: Article
• Language: English; English
• Published: Springer Publishing Company 2009
• Online Access: http://psasir.upm.edu.my/id/eprint/15008/1/High%20temperature%20impedance%20spectroscopy%20study%20of%20non.pdf; http://psasir.upm.edu.my/id/eprint/15008/; http://www.materialsscience.pwr.wroc.pl/
• Institution: Universiti Putra Malaysia

Single phase non-stoichiometric bismuth zinc niobate, Bi3Zn1.84Nb3O13.84, was fabricated by a conventional solid state method. The sample was refined and fully indexed on the cubic system, space group Fd3m (No. 227), Z = 4 with a = 10.5579(4) �. Electrical characterisation was performed using an ac impedance analyser over the temperature range of 25-850 �C and frequency range of 5 Hz-13 MHz. Typical dielectric response is observed in Bi3 Zn1.84Nb3O13.84 with a high relative permittivity, low dielectric loss and a negative temperature coefficient of capacitance, with the values of 147, 0.002 and -396 ppm/�C, at 100 kHz at ambient temperature, respectively. This material is highly resistive, with a conductivity of 1�10-21 O-1�cm-1 and a high activation energy of ca. 1.59 eV.