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Structure and phase transitions in 0.5(Ba0.7Ca0.3TiO3)-0.5(BaZr0.2Ti0.8O3) from −100 °C to 150 °C

2013; American Institute of Physics; Volume: 113; Issue: 1 Linguagem: Inglês

10.1063/1.4772741

1520-8850

Astri Bjørnetun Haugen, Jennifer S. Forrester, Dragan Damjanović, Binzhi Li, Keith J. Bowman, Jacob L. Jones,

Multiferroics and related materials

The solid solution of (x)Ba0.7Ca0.3TiO3-(1-x)BaZr0.2Ti0.8O3 is known to exhibit high piezoelectric constants. Discrepancies in the reported phase transitions and structure around room temperature, however, have complicated the understanding of the enhanced properties. Rietveld refinement of high-resolution X-ray diffraction is employed here to establish and refine the crystallographic structure at temperatures from −100 °C to 150 °C for x = 0.5. A combination of rhombohedral R3m and tetragonal P4mm is found to coexist at temperatures of 20 °C and −25 °C, bordered by single phase rhombohedral and tetragonal regions at lower (i.e., −100 °C) and higher (i.e., 70 °C) temperatures, respectively. The diffractograms also show signs of strain and domain wall scattering that are linked to the sample history.