High-pressure x-ray absorption spectroscopy: Application to the local aspects of phase transitions in ferroelectric perovskites

Abstract

X-ray absorption spectroscopy (XAS) provides information on the local order around a given atom. Under high pressure, this technique has been shown to be very sensitive to phase transitions. The evolution of the local structure of ferroelectric titanates under high pressure is obtained using XAS showing that the Ti atom remains out of the center of the surrounding oxygen octahedron just above the transition to the cubic structure and goes to the center at higher pressure. For BaTiO3 this effect is directly related to the lost of diffuse lines observed in the x-ray diffraction pattern. © 2010 Springer Science+Business Media B.V.