PHYSICAL-PROPERTIES OF HYDROTHERMALLY GROWN GALLIUM ORTHOPHOSPHATE SINGLE-CRYSTALS

GaPO4 single crystals have been hydrothermally grown by the horizontal temperature gradient method. The physical properties of these single crystals were measured. The following results were obtained: lattice parameters a = 0.490 nm and c = 1.105 nm, density ρ{variant} = 3.56 g cm-3, Vickers hardness Hv = 7.06 × 109 Nm-2, refractive indices ne = 1.611±0.006 and n0 = 1.599±0.006, and birefringence Δn = +0.012. GaPO4 single crystals exhibited some similar properties to α-quartz and AlPO4 single crystals because of the similarity of their crystal structures. © 1990 Chapman and Hall Ltd.