Growth and Thermophysical Properties of the Nonlinear Optical Crystal LuAl3(BO3)4
journal contributionposted on 22.02.2016, 17:45 by Shenghao Fang, Hua Liu, Ning Ye
Single crystals of LuAl3(BO3)4 (LuAB) have been grown with the top-seeded solution growth method from a new tungstate based flux Li2WO4–B2O3. The crystallization region of LuAB is revealed in a quasi-ternary system of LuAB–Li2WO4–B2O3. Correlation between the crystallization region of LuAB and an excess of Al2O3 in the flux system has been identified for the first time. Compared with the commonly used K2Mo3O10–B2O3 flux at 1100 °C, the Li2WO4–B2O3 flux has lower volatility with lower incorporation of tungstate into the crystals. Thermophysical properties of the crystal have been investigated for the first time, where the thermal expansion coefficients along two crystallographic directions in the temperature range of 30–800 °C were determined to be α1 = 3.38 × 10–6 K–1 and α3 = 10.4 × 10–6 K–1. The specific heat was about 0.65 J/(g·K) at room temperature. The thermal conductivities at room temperature were 12.47 W/(m·K) and 10.443 W/(m·K) along the a and c axes, respectively, and the Vickers hardness values were measured at 1449 (HV) for (100) and 1595 (HV) for (001) faces.