Structural analysis of Li2TiO3 by synchrotron X-ray diffraction at high temperature

The crystal structure at high temperature and the thermal expansion properties of Li2TiO3, important for use as a tritium breeding material in fusion reactors, have been investigated with high resolution by using high temperature synchrotron X-ray diffraction. The temperature dependence of lattice constants and molar volumes were calculated from the data, and variation of thermal expansion around 450-500 deg. C has been more clearly observed than from high temperature X-ray diffraction using Cu Kα radiation. The variation of thermal expansion can be attributed to existence of a higher order phase transition or appearance of nonlinear thermal expansion.