Growth and electro-physical properties of some monocrystals of Pb - Te - o system

Using the spontaneoUs crystallization method β-PbTeO3 Pb3TeO5-PbO cut-TeO2 and Pb3TeO6-PbTeO4 cut-PbO monocrystals of the Pb-Te-O ternary system are prepared from molten solution α-PbTeO3 and Pb2Te3O8 crystals are grown from the PbO-TeO2 cut by the Czochralski method. As a result of dielectric, roentgenographic and nonlinear optical studies in β-PbTeO3 crystals at 530 K and in Pb3TeO6 crystals at 490 K a reversible phase transition is observed. The conclusion is made that below phase transition points β-PbTeO3 and Pb3TeO6 are in the spontaneously polarized state, and in Pb2Te3O8, Pb3TeO5, α-PbTeO3 dielectrics no phase transitions are observed in the 120-800 K temperature range