Thermal conductivity of single crystals of Ca1 − xErxF2 + x and Ca1 − xTmxF2 + x solid solutions

The thermal conductivity of single crystals of Ca 1 − x Er x F 2 + x ( x = 0.01, 0.05, 0.07, and 0.10) and Ca 1 − x Tm x F 2 + x ( x = 0.02, 0.04, and 0.06) solid solutions is studied in the temperature ranges 50–300 and 298–673 K. With increasing content of rare-earth elements, the behavior of thermal conductivity in these solid solutions changes from the characteristic of defect single crystals to glasslike. The concentration dependences of thermal conductivity for the two systems differ insignificantly.