AN X-RAY-SCATTERING STUDY OF THE LOW-TEMPERATURE PHASE-TRANSITIONS OFLIKSO4

X-ray diffraction studies on solution-grown LiKSO4 have been performed between 70 K and 300 K. The lattice parameters have been obtained as a function of the temperature. The hexagonal to trigonal phase transit ion at 205 K is seen by a slight increase of the c lattice parameter, while the ferroelastic transition at 182 K is accompanied by the appea rance of an important spontaneous elastic deformation. The deformation and the domain pattern are analysed via a 'squeezing' model of the he xagonal lattice which leads to a monoclinic lattice below T-c = 182 K.