Investigation of conduction and relaxation phenomena in BaZr x Ti 1  x O 3 (x ¼ 0.05) by impedance spectroscopy Sandeep Mahajan a,c,n , Divya Haridas b , S.T. Ali a , N.R. Munirathnam a , K. Sreenivas c , O.P. Thakur d , Chandra Prakash d a Centre for Materials for Electronics Technology (C-MET), IDA Phase-III, Cherlapally, HCl (PO), Hyderabad-500051, India b Keshav Mahavidyalaya, H-4-5 Zone, Sainik Vihar Pitampura, Delhi-110034, India c Department of Physics and Astrophysics, University of Delhi, Delhi-110054, India d Solid State Physics Laboratory, Lucknow Road, Delhi-110054, India article info Article history: Received 23 April 2014 Received in revised form 26 June 2014 Accepted 27 June 2014 Available online 7 July 2014 Keywords: Electronic materials Dielectric properties Impedance spectroscopy BZT Ceramic abstract In present study we have prepared ferroelectric BaZr x Ti 1 x O 3 (x ¼0.05) ceramic by conventional solid state reaction route and studied its electrical properties as a function of temperature and frequency. X- ray diffraction (XRD) analysis shows single-phase formation of the compound with orthorhombic crystal structure at room temperature. Impedance and electric modulus spectroscopy analysis in the frequency range of 40 Hz–1 MHz at high temperature (200–600 1C) suggests two relaxation processes with different time constant are involved which are attributed to bulk and grain boundary effects. Frequency dependent dielectric plot at different temperature shows normal variation with frequency while dielectric loss (tanδ) peak was found to obey an Arrhenius law with activation energy of 1.02 eV. The frequency-dependent AC conductivity data were also analyzed in a wide temperature range. & 2014 Elsevier B.V. All rights reserved. 1. Introduction Barium titanate (BaTiO 3 ) is a well known perovskite ferro- electric material, which shows interesting structural transitions as well as ferroelectric transitions. Historically, it was the first polycrystalline ferroelectric which has attracted lot of attention due to their functional electrical properties which find potential applications in various technologies like piezoelectric sensors, actuators, micro-electromechanical systems [MEMS], multilayer ceramic capacitors [MLC] and electro-optic devices with some additives [1–7]. Useful properties for commercial device applica- tions have been mostly observed originally in lead based perovs- kite compounds, such as PMN-PT, PNN-PZT, PLZT and PZT [6,8–10]. These compositions have an obvious disadvantage of volatility and toxicity of ‘lead’. Manufacturers are now being refrained from using materials especially those containing lead. Therefore in recent years research efforts have been directed more towards the development of environmental friendly ‘lead-free’ composi- tions. However before replacing the well established PbZr x Ti 1 x O 3 (PZT) based ceramics in commercial applications, it is becoming necessary to understand the newly developed lead free composi- tions, optimize their processing and tailor the compositions for specific properties. It is well known that phase transition temperatures in BaTiO 3 can be altered by doping with either A or B site substitutions. Zr doping in BaTiO 3 formed a solid solutions for all substitution range and received extensive attention due to its eminent dielectric performance which is useful for commercial device application [6,11–13]. Compositional variation of Zr in range (0.03 rx r0.08) is found to exhibit excellent piezoelectric properties, and with higher Zr concentration (x upto 0.4) a typical relaxor behavior is observed [13]. Dixit et al. studied the BaZr x Ti 1 x O 3 system in the composition range 0.30 rx r0.70 in thin-film form and so far, many researchers have studied the dielectric properties of BaZr x- Ti 1 x O 3 system in higher substitution range [14,15]. Maiti et al. has studied the composition behavior across the complete phase diagram of BaZr x Ti 1 x O 3 (0.00 rx r1.00) and reported the depen- dence on composition, properties extending from simple dielectric (pure BaZrO 3 ) to polar cluster dielectric, relaxor ferroelectric, second order like diffuse phase transition, ferroelectric with pinched phase transitions and then to a proper ferroelectric (pure BaTiO 3 ) with bottom-up approach [16]. At x Z0.10 BaZr x Ti 1 x O 3 (BZT) solid solution exhibits a pinched phase transitions into a Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/physb Physica B http://dx.doi.org/10.1016/j.physb.2014.06.035 0921-4526/& 2014 Elsevier B.V. All rights reserved. n Corresponding author at: Centre for Materials for Electronics Technology (C-MET), IDA Phase-III, Cherlapally, HCl (PO), Hyderabad-500051, India. Tel.: þ91 40 27267006; fax: þ91 40 27261658. E-mail address: sandeepmahajan02@yahoo.com (S. Mahajan). Physica B 451 (2014) 114–119