Low-temperature synthesis of materials in the SrF<sub>2</sub>–ScF<sub>3</sub> system and study of their electrical conductivity

Using the “soft chemistry” method (precipitation of HF from aqueous solutions of strontium chlorides SrCl2 and scandium chloride ScCl3) nanocrystalline samples of (100 − x) SrF2 × xScF3, 3 ≤ х ≤ 33 mol % compositions with an average grain size of ~20 nm were synthesized. From a solution of 95SrCl2 × 5ScCl3 a single-phase solid solution of Sr0.97Sc0.03F2.03 with a fluorite structure (CaF2-type, space group F) with a unit cell parameter a = 5.7959 ± 0.0016 Å was obtained. On a ceramic sample prepared from it by cold pressing and heated to a temperature of 831 K, the ionic conductivity in the cooling mode was measured, which is 6.4 × 10−6 S/cm at 673 K. The activation energy of ion transfer is 1.13 ± 0.04 eV. The conductivity of nanocrystalline Sr0.97Sc0.03F2.03 exceeds the electrical conductivity of a single crystal of the same composition by 3.5 times and is ~10 times less than the electrical conductivity of a single crystal Sr0.92Sc0.08F2.08.