Thermal properties of Er:Li2TiGeO5 ferroelastic ceramics

Micron-grained (2–11 μm), erbium-doped, polycrystalline lithium titanium germinate ceramics were fabricated out of the heat-treated of the presintered samples at a temperature of 970 °C. X-ray diffraction showed a high crystallinity of the synthesized ceramics and confirmed formation of the natisite type structure with the P4/nmm symmetry. FE-SEM analysis revealed that the microstructure of obtained ceramics depends on dopant concentration. The number of pores increases with increasing the dopant dose. The specific heat measurements showed that the temperature of the ferroelastic phase transition was significantly reduced for Li2TiGeO5 ceramics (222 K) compared to the bulk (233.5 K). The investigations of the thermal conductivity showed its untypical behavior, proportional to the square of temperature, for a dielectric at low temperatures which could be explained by the microstructure of the samples.