Structure evolution in La(Mg0.5Ti0.5)O3–SrTiO3 system

Crystal structure transformations of dielectric ceramics in the (1−x)La(Mg0.5Ti0.5)O3 (LMT)–xSrTiO3 (ST) [0<x<1] system were studied using Rietveld analysis of X-ray powder diffraction data. LMT and ST form a solid solution in all the compositional range. Increase of SrTiO3 content results in the following sequence of structure transformations: P21/n (a−a−c+, B-site ordered)→Pbnm (a−a−c+)→Imma (a−a−c0)→I4/mcm (a0a0c−), which are related to the disappearance of B-site cation ordering (x>0.1), in-phase tilting (x>0.5), and transition from anti-phase two-tilting to one-tilting system (x>0.7), respectively.