Ion Transfer in CdF2-based Iso- and Polyvalent Solid Solutions

Abstract

The ionic conductivity of solid solution Cd 0.77 Sr 0.23 F 2 is 1.6 × 10 -4 S/cm at 500 K. The conduction mechanism changes from a vacancy mechanism to an interstitial one at 523-553 K. In solid solutions Cd 0.9 R 0.1 F 2.1 (R = La-Lu, Y), the activation enthalpy of conduction decreases from 0.9 to 0.8 eV with decreasing ionic radius of R 3+ , raising the 500-K conductivity from 6 × 10 -6 S/cm for La 3+ to 6 × 10 -5 S/cm for Lu 3+ . For crystalline Cd 0.95 In 0.05 F 2.05 , ionic and electronic conductivities at 313 K equal 5 × 10 -4 and 5 × 10 -6 S/cm.

Effect of iso- and heterovalent cation substitutions on the superionic Faraday transition in fluorite-type modification β-PbF-=SUB=-2-=/SUB=-

“…In the system PbF 2 −CdF 2 , a complete isomorphism of components (0 ≤ x ≤ 1) is implemented, while in the system PbF 2 −ScF 3 there is a partial isomorphism of components (0 ≤ x ≤ 0.15). Choice of compositions of the studied crystals Pb 0.67 Cd 0.33 F 2 (composition corresponds to the minimum on the melting curve) and Pb 0.9 Sc 0.1 F 2.1 is due to the fact that they have the maximum values σ dc among Pb 1−x Cd x F 2 and Pb 1−x Sc x F 2+x [34,35] solid solutions. For comparative analysis, we measured the electrical conductivity of a β-PbF 2 single crystal doped with a small amount of scandium.…”

“…The σ dc (T ) dependences were measured in the range from room temperature (293 K) to 873 K in a nitrogen atmosphere N 2 or vacuum (∼ 1 Pa). A detailed description of the experimental setups and the results of conductometric studies of crystals are published in [34,[36][37][38][39].…”

10.1007/s11445-008-2016-0

“…The physical properties of M 1y F 2 crystals are being actively investigated [11][12][13][14][15]. Correlations have been found [12,[16][17][18] which relate the ionic conductivity, microhardness, and the characteristics of light scattering spectra to the formation of minima on the melting curves of isovalent M 1y F 2 solid solutions.…”