Ionic transport studies were made of fluorite phases which had rare-earth trifluoride contents of 20 to 40mol%. The crystals were prepared by using the Stockbarger technique, and impedance spectroscopy was used to measure the conductivity in a vacuum of about 0.01Pa. It was found that the results for each composition could be described by a Frenkel-type law. The conductivity of Ca0.70Yb0.30F2.30, at temperatures ranging from 525 to 761K, could be described by:

σT (SK/cm) = 1.89 x 104 exp[-0.824(eV)/kT]

The conductivity at 500K was equal to 1.9 x 10-7S/cm.

A.K.Ivanov-Shits, N.I.Sorokin, E.A.Krivandina, A.A.Samokhina, B.P.Sobolev: Elektrokhimiya, 1988, 24[11], 1571-4 (Soviet Electrochemistry, 1988, 24[11], 1458-61)