Floating-zone growth and characterization of single crystals of manganese orthosilicate, Mn 2 SiO 4

Using a floating zone technique and a passive afterheater, crack-free single crystals of manganese orthosilicate, Mn2SiO4, were grown along the three principle orientations in a reducing gas atmosphere at atmospheric pressure. The grown crystals were typically 5–7mm in diameter and 20–40mm in length. Well-developed facets were found on the periphery of some of the crystals grown along the [100] orientation (space group: Pbnm). Laue back reflection was used to determine orientations of grown crystals and of facets formed at outer surfaces. Dislocation densities ranging between 105 and 106cm−2 were determined by optical microscopy after polishing and chemical etching. By using X-ray powder diffraction it was determined that a thermodynamically favored decomposition of grown single crystals of manganese silicate during cooling after crystal growth did not occur. Concentrations of impurities and the degree of a desired silica excess present in the grown crystals were determined by using the ICP-AES technique. The presence of intended silica-rich precipitates was confirmed by electron microprobe analysis.