Properties of Pb_0.71K_0.145Sm_0.145Nb₂O₆ analysed within piezoelectric, dielectric, impedance, electric modulus and conductivity

¹ Centre for Piezoelectric Transducer Materials, Department of Physics, Andhra University, Visakhapatnam – 530 003, India
² Department of Inorganic Materials Engineering, Kyungpook National University, Daegu, 702701, Korea

Corresponding author: konapala@sify.com

Received: 23 May 2007
Revised: 7 November 2007
Accepted: 8 January 2008
Published online: 9 April 2008

Abstract

Orthorhombic tungsten bronze PbKSm_yNb₂O₆ (where x = 0.29 and y = 0.145) ceramic has been synthesized by the conventional sintering technique. Preliminary X-ray diffractogram analysis of crystal structure showed that a single phase compound has been formed with orthorhombic system. Frequency and temperature dependences of impedance, modulus, conductivity and dielectric permittivity have been performed in the frequency and temperature range 45 Hz–5 MHz and 35–595 °C respectively. Impedance spectroscopy study showed the presence of both bulk and grain boundary effects in the materials. The complex impedance spectra above 440 °C have been fitted by the superposition of two Cole-Cole types of relaxations. The ac conductivity spectrum obeyed the Jonscher's power law. Modulus analysis indicated the possibility of hopping mechanism for electrical process in the system.