Papers by Author: An Hua Wu

Abstract: YFeO3 single crystal, as a novel magneto-optical material, has attracted much attention due to its remarkable properties of primary significance for technological applications. In this work, YFeO3 crystal was successfully grown by optical floating zone method. Some voids are observed in the polished surface. The voids are effectively decreased by denser feed rod. In the etching samples, hexagonal etch patterns, sub-grain boundary and concentric growth striations were observed by optical microscope and SEM. The formation mechanism of these defects was discussed, and effective measures to restrain these defects were also proposed.

Abstract: Langasite (La3Ga5SiO14, LGS) and its isomorphs, were regarded as potential substrate materials for surface acoustic wave (SAW) and bulk acoustic wave (BAW) applications. Among these homologous compounds, the ordered structure crystals have attracted much attention for their low Ga2O3 content, high acoustic velocity and low acoustic loss. In this work, the ordered langasite structure crystals Ca3NbGa3Si2O14 (CNGS) were grown with vertical Bridgman method for the first time. The CNGS crystals with 25mm in diameter and 40mm in length were grown successfully from its stoichiometric melt through LGS crystal of Ø10mm×40mm being chosen as seed. X-ray powder diffraction experiments showed that the CNGS single crystals had a single phase and had the same structure as the LGS crystal. The transmittance spectra with the wavelength from 200 to 800nm were recorded by means of Spectrophotometer at room temperature.