Crystal structure and microwave dielectric properties of La(Mg_1/2Ti_1/2)O₃ ceramics

The temperature stability and the Q-value of microwave ceramics are largely affected by the crystal structure. La(Mg_1/2Ti_1/2)O₃ (LMT) has the 1:1 ordered monoclinic crystal structure with the lattice parameters of a = 5.5467 angstroms, b = 5.5616 angstroms, c = 7.8426 angstroms and β = 89.9589°. The spacegroup of the ceramic material is P2₁/n. Monoclinic LMT is distorted by in-phase and anti-phase tilting of octahedra with the a^-a^-c⁺ tilting system. An anti-parallel shift of A-site cations is also found in LMT. The relative density of the specimens sintered above 1600 °C ranged between 95% and 96% of the theoretical density and the dielectric constant of the specimens is about 28.