Thermal properties of Sr 3Ga 2Ge 4O 14 single crystals grown by the vertical Bridgman method

Abstract

Sr 3Ga 2Ge 4O 14 (SGG) has been grown by the vertical Bridgman method. The dielectric constants ε 11 T and ε 33 T at room temperature is 13.61 and 18.18, respectively. The dielectric measurements show that SGG crystals display relative high temperature stability and high frequency stability. Thermal properties including specific heat, thermal diffusivity, thermal conductivity and thermal expansion have been investigated as a function of temperature for the first time. The specific heat of the SGG crystals has been measured to be 0.459 J/(g K) at 298 K. The thermal diffusivity and the thermal conductivity for SGG crystals are about 0.540 mm 2/s and 1.243 W/(m K) at 298 K, respectively. The average thermal expansion coefficients along the a- and c-directions of SGG crystals, are calculated from 298 to 973 K as α 11 = 6.5 × 10 −6 K −1 and α 33 = 5.8 × 10 −6 K −1, respectively.