Floating zone growth and optical phonon behavior of corundum Mg4Ta2O9 single crystals

We demonstrate that corundum Mg4Ta2O9 crystals, free of low-angle grain boundaries and bubbles, were prepared for the first time by the infrared heating optical floating zone method. The X-ray diffraction results showed that the crystals had corundum structure, cleaved parallel to the c plane and grew along the a-axis. The temperature-dependent optical phonon behavior of Mg4Ta2O9 were also investigated in the range from 84 to 834 K.