Growth and thermal properties of LaCa4O(BO3)3 crystals

Abstract A nonlinear optical crystal of LaCa4O(BO3)3 (LaCOB) of large size and good optical quality has been grown by the Czochralski method. X-ray diffraction experiments show that the crystal has the same structure as that of YCa4O(BO3)3 and its unit cell constants have been measured to be a=0.8168(3) nm, b=1.6081(7) nm, and c=0.3630(6) nm with an angle β=101.39°. The thermal properties of LaCOB have to our knowledge been studied for the first time. The specific heat of the crystal has been measured to be 308.3 J/mol K at 300 K. The three principal coefficients of thermal expansion of the crystal and the orientation of the principal axes have been calculated from the measured data to be 5.61×10−6, 7.21×10−6, 11.01×10−6 K−1 and 4.4°, respectively.