Growth, structure, dielectric behavior and AC-conductivity of pyrochlore lead-scandium tantalate single crystals

The conditions for growing monocrystals of the PbScTaO system by the high-temperature solution growth method were optimized. The elemental analysis revealed their composition is Pb1.944(Sc0.506Ta1.494)O6.438. X-ray diffraction analysis showed a cubic pyrochlore-type structure (space group Fd3m) with lattice parameter a = 10.6311(3) Å. The dielectric constant and the dielectric losses are measured in the temperature range 100–600 K and frequency range 102–107 Hz. From the real and imaginary part of the AC conductivity, it is concluded that the charge transfer is accomplished through hoppings between localized states.