Anisotropy of the ionic conductivity in potassium bismuth/rare earth molybdate crystals

Anisotropy of electrical and dielectric properties, self-diffusion of K+ ions, and phase transitions in stoichiometric disordered K5Bi1−xRx(MoO4)4 (R = Nd, Gd; x = 0, 0.92, 1) single crystals are studied. A high value of the 2-D ionic conductivity by K+ ions (10− 3 S/cm, at 495 °C) is found in all samples. The fast ionic transport is parallel to the double layers formed by MoO4 tetrahedra.