High Temperature Dielectric Relaxation And Impedance Spectroscopy Studies On BaBiO3 

Magnetics & Advanced Ceramics Laboratory, Physics Department, Indian Institute of Technology Delhi, New Delhi 110016, India

Adv. Mater. Lett., 2016, 7 (8), pp 604-609

DOI: 10.5185/amlett.2016.6236

Publication Date (Web): Jul 01, 2016

Copyright © IAAM-VBRI Press

E-mail: rmala@physics.iitd.ac.in

Abstract

BaBiO₃ (BBO) particles were successfully synthesized through solid-state route, to provide better understanding of its transport properties, which is not well studied yet. X-ray diffraction (XRD) measurement confirmed that the particles were crystallized with monoclinic structure in single phase. The Raman spectrum of BBO sample revealed the existence of two different Bi sites (the octahedral BiO_6/3 and the triangular pyramidal BiO_4/2 cluster). Subsequently, the observation of low resolution and lattice scale imaging through high resolution transmission electron microscope (HRTEM) indicated the formation of monoclinic BBO particles of size ~ 50-60 nm. The ring pattern obtained from selected area electron diffraction (SAED) inveterate polycrystalline nature of the sample and calculated structural parameters well harmonized with XRD results. As expected, BBO showed semiconducting behavior with resistivity of ~ 3.8 kΩ-cm at room temperature along with an excellent NTC (negative temperature coefficient) thermistor characteristic. The dielectric measurements and impedance spectroscopy studies reveal that BBO exhibit two typical characteristics, i.e., diffuse phase transition and frequency dependent dielectric maxima, of relaxor oxides; with negative dielectric constant above 550 K.

Keywords

Rietveld refinement, Raman spectroscopy, electron microscopy, dielectric properties and impedance spectroscopy.