Ion conduction in one-dimensional ionic conductors Mg-, Rb- and Al-doped KxGa8Ga8+xTi16−xO56 single crystals
Abstract Ion conduction in single crystals of one-dimensional (1D) superionic conductors Mg-, Rb- and Al-doped potassium gallotitano-gallate, which were attributed as KGMGTO, KRGGTO, and KGAGTO, was studied by an ac complex electrical conductivity measurement from 100 Hz to 38 GHz. The aim of doping is to deduce the number of the interstitial (O 2– , Ga 3+ ) ion pairs, which block the collective motion of K + ions, for enhancement of K + ion conduction without heat treatment. The observed frequency dependence of the ionic conductivity could be explained by the newly proposed ion conduction model. Most of the blocks could not be reduced by the doping of Mg 2+ ions. Doping of Rb + ions contributed to the removal of the blocks. In heavily Al-doped KGAGTO, the thermal treatment, which enhanced the K + ion conduction in an undoped crystal (KGGTO), did not have much effect on the enhancement of the K + ion conduction.