Crystal structure of dielectric ceramics in the La(Mg0.5Ti0.5)O3-BaTiO3 system

The crystal structure of microwave dielectric ceramics in the (1 - x)La(Mg0.5Ti0.5)O-3 (LMT)-xBaTiO(3) (BT) (0 less than or equal to x less than or equal to 0.9) system has been refined by Rietveld method using x-ray powder diffraction data. LMT and BT were found to form a solid solution in the whole compositional range. The increase of BaTiO3 content results in the following sequence of structure transformations of those solid solutions: P2(1)/n (a(-)a(-)c(+), B-site ordered) --> Pbnm (a(-)a(-)c(+)) --> I4/mcm (a(0)a(0)c(-)) --> Pm3m (a(0)a(0)a(0)). These structural changes are related to the disappearance of B-site cation ordering (x > 0.1), in-phase tilting (x > 0.3), and antiphase tilting (x > 0.5), respectively.