Thermal conductivity of single crystals of Ba1–x R x F2 + x (R = La, Ce, Nd, or Gd) solid solutions

Abstract

The thermal conductivity of single crystals of Ba1–х R х F2 + х (R = La, Ce, Nd, or Gd) solid solutions has been experimentally investigated in the temperature range of 50–300 K. With an increase in the content of rare-earth elements, the thermal-conductivity behavior in these series changes from that characteristic of defect single crystals to the behavior typical of glasslike materials. The thermal-conductivity concentration dependences are almost identical, which can be explained by the same type of defect clusters arising upon heterovalent ion substitution.