Numerical model of temperature-dependent thermal conductivity in $M_{1-x}R_x\mathrm{F}_{2+x}$ heterovalent solid solution nanocomposites where $M$ stands for alkaline-earth metals and $R$ for rare-earth metals

We propose a mathematical model to fit the temperature-dependent thermal conductivity of $M_{1-x}R_x\mathrm{F}_{2+x}$ heterovalent solid solutions where $M$ stands for alkaline-earth metals and $R$ for rare-earth metals. These solid solutions experience composition-driven transition from the crystal-like to glass-like behavior of thermal conductivity. When tested on $\mathrm{Ca}_{1-x}\mathrm{Yb}_x\mathrm{F}_{2+x}$ solid solutions, the model showed a potential for use with an option for further improvements.