Electronic structure and bonding interactions in Ba_1--xSr_xZr_0.1Ti_0.9O₃ ceramics

Abstract

An investigation on the precise electronic structure and bonding interactions has been carried out on Ba_1−xSr_xZr_0.1Ti_0.9O₃ (short for BSZT, x = 0, 0.05, 0.07 and 0.14) ceramic systems prepared via high-temperature solid state reaction technique. The influence of Sr doping on the BSZT structure has been examined by characterizing the prepared samples using PXRD, UV-visible spectrophotometry, SEM and EDS. Powder profile refinement of X-ray data confirms that all the synthesized samples have been crystallized in cubic perovskite structure with single phase. Charge density distribution of the BSZT systems has been completely analyzed by the maximum entropy method (MEM). Co-substitution of Sr at the Ba site and Zr at the Ti site into the BaTiO₃ structure presents the ionic nature between Ba and O ions and the covalent nature between Ti and O ions, revealed from MEM calculations. Optical band gap values have been evaluated from UV-visible absorption spectra. Particles with irregular shapes and well defined grain boundaries are clearly visualized from SEM images. The phase purity of the prepared samples is further confirmed by EDS qualitative spectral analysis.

Keywords

barium titanate / X-ray diffraction / Rietveld refinement / maximum entropy method / bonding

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Acknowledgements

The authors gratefully acknowledge the authorities of “The Madura College, Madurai-11” for providing lab facilities, continuous support and encouragement to carry out the research work successfully. One of the authors (J.M.) is thankful to the Management of NMSSVN College, Nagamalai, Madurai-19 and UGC for the Faculty Development Programme of XII plan, the period in which this effective work was carried out.

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