Phase transitions and ionic transport in K3InF6

Four allotropic forms are shown for the K3InF6 ternary fluoride by various experimental investigations, microcalorimetry, high temperature X-ray diffraction, optical and electrical measurements. The ac conductivity data of K3InF6 are analysed in the Z*, M* and ε* formalisms and the conductivity relaxation parameters are determined. Conductivity is of Arrhenius-type on either side of a transition temperature Ttr (Ttr=488±10 K) which is very close to the Curie temperature TC (TC=480±5 K). A conductivity jump of about one decade is observed at TC and that transition is of ionic-superionic type.