Temperature dependence of 7Li NMR in a LiKSO 4 single crystal

Abstract

The temperature dependence of the 7Li nuclear magnetic resonance in a LiKSO 4 single crystal grown by the slow evaporation method was investigated by employing a Bruker FT NMR spectrometer. The 7Li NMR spectra demonstrates the occurrence of the first-order phase transition at 190 K which is connected with a lowering of the Li + site symmetry and formation of three kinds of ferroelastic domains. Below and above 190 K, the quadrupole coupling constants and asymmetry parameters of Li in LiKSO 4 decrease as the temperature increases. The temperature dependence of the quadrupole parameters in the temperature range of 130–400 K is explained by a single torsional frequency of the LiO ion by means of the simple Bayer theory.