Raman results in the Na β- and β″-gallate superionic conductors

Raman results of two superionic conducting materials, Na β-and β″-gallate, are reported. The spectra divide clearly into a high energy part, above 160 cm-1, and a low energy part that varies as Na is replaced with K or Rb. The low energy line, associated with the so called attempt frequency, occurs at 57 and 69 cm-1 for Na β- and β″-gallate respectively. Rather surprisingly, the lines are much narrower than observed in the aluminate analogues. We measure 5.6 and 3.0 cm-1 respectively. The high energy lines are very similar for the β- and β″-gallate crystals. © 1976.