Anisotropic thermal properties of the polar crystal Cs2TeMo3O12

A Cs2TeMo3O12 single crystal with dimensions of 17 mm×17 mm×18 mm was grown using the top-seeded solution growth method. Thermal properties, including thermal expansion, specific heat, thermal diffusivity and thermal conductivity, were investigated as a function of temperature. The average linear thermal expansion coefficients along different crystallographic directions were measured to be αa=7.34×10−6 K−1 and αc=32.02×10−6 K−1 over the temperature range of 30–430 °C. The specific heat was measured to be 0.400–0.506 J g−1 K−1 from 22 °C to 440 °C. The thermal conductivity was calculated to be 1.86 and 0.76 W m−1 K−1 at 22 °C along the a and c axes, respectively. With increasing temperature from 22 to 430 °C, the thermal conductivity decreases by 33.0% along the a axis, while it decreases by 18.5% below 200 °C and then remains unchanged along the c axis. The relationship between structure and the thermal properties is also discussed.

Graphical AbstractCentimeter-sized crystals of polar Cs2TeMo3O12 were grown using the top-seeded solution growth method. The relative large anisotropy in thermal expansion and thermal conductivity of Cs2TeMo3O12 is attributable to its layered structure.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Cs2TeMo3O12 single crystals with dimensions of 17×17×18 mm3 were grown. ► Thermal properties of Cs2TeMo3O12 were studied as a function of temperature. ► The thermal expansion anisotropy of Cs2TeMo3O12 is explained using its structure. ► To protect Cs2TeMo3O12 crystal, a small cooling rate should be used during growth. ► A large temperature gradient should be avoided during processing and application.