| Research Abstract |
Ion conduction in single crystals of one-dimensional (1D) superionic conductors Mg_-, Al_-, and Rb-doped potassium gallotitanogallate, which were attributed as KGMGTO, KGAGTO, and KRGGTO, was studied by an ac complex electrical conductivity measurement from 100Hz 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 heat 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.
Ion conduction in one-dimensional superionic conductors alkali-garotitanogallate A_xGa_8Ga_<8+x>Ti_<16-x>O_<56>(AGGTO, A : K, Rb, or Cs) single crystals were studied by an ac electrical complex conductivity measurements between 10Hz to 59 GHz. It verified that the real part of the complex conductivity for RGGTO and CGGTO decreased with increasing frequency in the microwave region, because the upper limit of the measurement frequency was extended to 59 GHz from 38 GHz. Results were consistent with the proposed ion conduction model. The concentration of Cs^+ions in CGGTO was good agreement with the composition determined by the chemical analysis.
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