Growing and investigation of Bisub(4)GeVOsub(10.5) and Bisub(8)Psub(4-x)Gesub(1+x)Osub(24-x/2)

Monocrystals of the Bi4GeVO15 and Bisub(8)Psub(4-x)Gesub(1+x)Osub(24-x/2) (x=0.25) phases are obtained under conditions of slow melt cooling. Analysis of the chemical composition of crystals is made, their X-ray diffraction IR spectroscopy, dielectric and pyroelectric investigations are carried out. New data on phase crystallography are obtained; the crystals are found to manifest the pyroelectric effect at room temperature. The first-type phase transition between rhombic and tetragonal forms is observed by the methods of high temperature X-ray diffraction study in crystals of the Bisub(4)GeVOsub(10.5) phase at 550 K. Crystals of the Bisub(4)GeVOsub(10.5) phase are assigned to be ferrgelectrics with the Curie point equal to 550 C. The crystals of this phase are established to be close in structure to crystals of bismuth-containing compounds with laminated perovskite-like structures