Transition from crystal-like to glass-like behavior of thermal conductivity in the Sr0.16Ba0.54La0.30F2.30 solid solution

Using a steady-state axial flow technique, we have measured the thermal conductivity of single crystals of congruently melting SrF 2 -BaF 2 -LaF 3 solid solutions from 50 to 300 K: Ba 0.66 Sr 0.34 F 2 (minimum in the melting curves), Ba 0.70 La 0.30 F 2.30 (maximum in the melting curves), and Sr 0.16 Ba 0.54 La 0.30 F 2.30 (saddle point on the melting surfaces). The thermal conductivity of the isovalently doped fluorite solid solution is typical of crystals containing point defects. Heterovalent substitution leads to glass-like behavior of thermal conductivity.