Thermal Expansion of Nonlinear Optical Crystal La2CaB10O19

Abstract

The thermal expansion coefficients of the nonlinear optical crystal La2CaB10O19 (LCB) were measured along three crystallographic axes (a, b, c) and in another direction marked with d, which lay in the (010) plane with the angle between a and d equal to 45°. Thermal expansion measurements were carried out in the temperature range between 25°C and 300°C. The experimental data obtained were 8.642×10-6, 8.387×10-6, 2.266×10-6 and 5.813×10-6 K-1, respectively. The changes of lattice constants for a, b, and c were calculated. The three principle expansion coefficients were calculated to be 8.665×10-6 K-1, 8.387×10-6 K-1 and 2.261×10-6 K-1, respectively. The anisotropy of the structure of the La2CaB10O19 crystal leads to the anisotropic thermal expansion property.