EPR study of low-temperature phase transitions in NH3+-Doped LiKSO4

Abstract

The EPR spectra of the NH 3+ radical are used to probe the low temperature structural phase transitions of LiKSO4. Positional disorder of K+ ions proposed by Yu et al. is excluded. The low intensity lines accompanying the main EPR spectrum are explained in the “randomly oriented proton” model. Below about 190 K where the symmetry of EPR spectra lowers from axial to rhombic, the fragment of ferroelastic hysteresis loop is obtained from the EPR line intensity changing under uniaxial stress.