Growth and thermophysical properties of magneto-optical crystal TbVO4

Abstract

TbVO4 single crystal with high transmittance has been successfully grown by Czochralski method under highly pure nitrogen atmosphere, which could reduce the loss of growth crucible. The structure of as-grown crystal was verified by X-ray powder diffraction. The refraction indices measurement showed the crystal was an optical uniaxial crystal with large birefringence. The absorption coefficient was calculated taking account into transmittance and reflection, and the results indicated TbVO4 crystal had a low absorption at wavelength range of 440–1100 nm. Thermal properties of TbVO4 crystal were also measured. The specific heat is 0.472 J g−1 K−1 at room temperature. The thermal conductivities at room temperature are 7.216 W m−1 k−1 and 10.305 W m−1 k−1along the a and c directions respectively. XPS spectra showed there were two states of V which demonstrated oxygen vacancies existed in as-grown crystal. But Verdet constant of the crystal is about 60 rad T−1 m−1, and the figure of merit at 1064 nm is 28.9°/dB at 1.2 T, which is about twice than that of TGG. All the results indicate TbVO4 crystal is a candidate to the commercial magneto-optical material at visible and near-infrared regions.