The frequency response (10−1–10−7Hz) of the ionic conductivity σ of R1−yMyF3−y single crystals (R was a rare-earth element, and M stands for an alkaline-earth element and Cd) with a tysonite structure was studied over a wide temperature range (114–410K), which included (for the first time for these phases) the interval below room temperature. The dependences σ(ν) obtained were considered within the hopping relaxation model. The characteristics of the relaxation and migration processes and the carrier concentration and mobility were determined.

Frequency Response of the Low-Temperature Ionic Conductivity of Single Crystals R1−yMy F3−y (R = La-Er; M = Ca, Sr, Ba, Cd). N.I.Sorokin, B.P.Sobolev: Physics of the Solid State, 2008, 50[3], 416-21