Czochralski growth of Sr2Tb8(SiO4)6O2 crystals for visible–near IR magneto-optical applications

• Sr2Tb8(SiO4)6O2 (STS) crystals were grown by the Czochralski method.
• The magnetic property was characterized by magnetic susceptibility from 2 to 300 K.
• STS crystal shows a higher visible transparency than Tb3Ga5O12 (TGG).
• STS crystal exhibits superior magneto-optical properties.
• The Verdet constants of STS crystal are between 65% and 75% larger than those of TGG.

Sr2Tb8(SiO4)6O2 crystals have been grown and investigated for the first time for magneto-optical applications. The X-ray powder diffraction confirms that the compound crystallizes in the hexagonal system, with a common oxyapatite structure. The as-grown crystal exhibits low thermal expansion anisotropy (αa/αc ≈ 1.1), and the hardness is about 5.0 Moh. The temperature dependence of the magnetic susceptibility indicated that the Sr2Tb8(SiO4)6O2 crystal exhibits paramagnetic behavior over the experimental temperature-range 2–300 K. The present investigations demonstrate that Sr2Tb8(SiO4)6O2 crystals show a higher visible transparency and a larger Faraday rotation than terbium gallium garnet (TGG) crystals. Sr2Tb8(SiO4)6O2 is therefore a very promising material in particular for new magneto-optical applications in the visible–near IR wavelength region.