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Lead-free perovskite Ba(Fe 1/2 Nb 1/2 )O 3 (BFN) was prepared by conventional ceramic fabrication technique at 1200 8C/5 h in air atmosphere. The crystal symmetry, space group, and unit cell dimensions were determined from the experimental results using FullProf software whereas crystallite size and lattice strain were estimated from Williamson-Hall approach. X-ray diffraction (XRD) analysis of the compound indicated the formation of a single-phase monoclinic structure with the space group P2/m. EDAX and SEM studies were carried out in order to evaluate the quality and purity of the compound. To find a correlation between the response of the real system and idealized model circuit composed of discrete electrical components, the model fittings were presented using the impedance data. Complex impedance analyses suggested the dielectric relaxation to be of non-Debye type. The correlated barrier hopping (CBH) model was employed to successfully explain the mechanism of charge transport in BFN.

Lead-free perovskite Ba(Al 1/2 Nb 1/2 )O 3 was prepared by conventional ceramic fabrication technique at 13501C/5 h in air atmosphere. The crystal symmetry, space group and unit cell dimensions were determined from the experimental results using FullProf software whereas crystallite size and lattice strain were estimated from Williamson-Hall approach. X-ray diffraction analysis of the compound indicated the formation of a singlephase monoclinic structure with the space group P2/m. EDAX and SEM studies were carried out in order to evaluate the quality and purity of the compound. Permittivity data showed lowtemperature coefficient of capacitance (T CC 5 14%) up to 1001C. To find a correlation between the response of the real system and idealized model circuit composed of discrete electrical components, the model fittings were presented using the impedance data. Complex impedance analyses suggested the dielectric relaxation to be of non-Debye type. The correlated barrier-hopping model was used to successfully explain the mechanism of charge transport in Ba(Al 1/2 Nb 1/2 )O 3 .

A new lead‐free perovskite ceramic Ba(Bi1/2Nb1/2)O3 was prepared by a conventional ceramic technique at 1185 °C in oxygen atmosphere. X‐ray diffraction analysis of the compound indicated the formation of a single‐phase monoclinic structure. Dielectric study revealed a diffuse phase transition at 340 °C. Cole–Cole analyses suggested the dielectric relaxation to be of non‐Debye type. Electric modulus studies supported the hopping type of conduction in Ba(Bi1/2Nb1/2)O3. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Lead free perovskite Ba(La 1/2 Nb 1/2 )O 3 was prepared by conventional ceramic fabrication technique at 1375uC for 7 h in air atmosphere. The crystal symmetry, space group and unit cell dimensions were estimated using Rietveld analysis. X-ray diffraction analysis indicated the formation of a single phase monoclinic structure with space group P2/m. Energy dispersive X-ray analysis and scanning electron microscopy studies were carried to study the quality and purity of the compound. Permittivity data showed low temperature coefficient of capacitance (T CC 511%) up to 100uC. The circuit model fittings were carried out using the impedance data to find the correlation between the response of real system and idealised model electrical circuit. Complex impedance analyses suggested the dielectric relaxation to be of non-Debye type. The correlated barrier hopping model was employed to successfully explain the mechanism of charge transport in Ba(La 1/2 Nb 1/2 )O 3 . The AC conductivity data were used to evaluate the density of states at Fermi level, minimum hopping length and apparent activation energy.