Determination of Ferro‐ and Antiferroelectricity Using the Temperature Dependence of the Pre‐Edge Features in the XANES Spectra: XANES Study of Tetragonal and Cubic ATiO3 (A = Sr, Ba, and Pb) and PbZrO3. Issue 11 (4th June 2018) - Yoshiasa, Akira
Abstract : The Ti and Zr K‐edge X‐ray absorption near edge structure (XANES) spectra of ATiO3 (A = Sr, Ba, and Pb) and PbZrO3 perovskite‐type compounds have been measured in the temperature range 20–900 K. Quantitative comparison is performed in a wide temperature range to clarify how the intensities of the pre‐edge peaks and shoulders change with temperature. In the ferro‐ and antiferroelectric tetragonal phases, the intensities of some of the peaks and shoulders decrease with increasing temperature and the peak‐top energies shift to the higher energy side. The shift can be explained by the position and decrease (increase for SrTiO3 ) of the D2 peak in the difference spectra. The peak‐top position of the pre‐edge peak in XANES does not always represent the true energy for independent transition to an orbital because several orbitals with similar energies overlap. The tetragonal SrTiO3 phase shows the same behavior as ferroelectric P 4 mm tetragonal BaTiO3 and PbTiO3 perovskite. The temperature dependence of the shoulder is also an important index. The presence of a phase with local polar tetragonal strain is important in materials and the Earth's constituent solid solutions. The existence of ferro‐ and antiferroelectricity can be determined by temperature‐dependent XANES measurements. Abstract : In the ferro‐ and antiferroelectric phases, the intensities of some of the pre‐edge peaks and shoulders in X‐ray absorption near edge structure (XANES) decrease with temperature and peak‐top energies shift to the higher energy side. The shift can be explained by the position and decrease of D2 peak in the difference spectra. Peak‐top position does not always represent the true energy for independent transition to an orbital.