Structural, dielectric and electrical properties of BaFe0.5Nb0.5O3 ceramic prepared by solid-state reaction technique

Barium iron niobate (BaFe0.5Nb0.5O3) has been prepared by solid state reaction route through heat treatment at 1200 degrees C for four hours in air. Structural properties have been investigated using X-ray diffraction (XRD), Raman spectroscopy, and Fourier transform infrared (FTIR) spectroscopy. Rietveld refinement technique has been employed to investigate the details of crystal structure and found to be cubic at room temperature with space group Pm-3m. The XRD patterns have been recorded from room temperature to 550 degrees C did not show any phase transformation. Raman spectra recorded from -100 degrees C to 550 degrees C did not show any structural change as a function of temperature variation. Temperature dependent dielectric behavior and d.c. conductivity have been investigated from room temperature to 550 degrees C. The dielectric study revealed two peaks; one for intrinsic and other for extrinsic type relaxation. Polarization study at various frequencies confirmed the hopping mechanism between Fe2+ and Fe3+ ions within the equivalent crystallographic sites of the sample. The material could be regarded as a canonical relaxor within 300 degrees C. (C) 2011 Elsevier B.V. All rights reserved.