Lower limit to the thermal conductivity of disordered crystals

Measurements of the thermal conductivity above 30 K of mixed crystals with controlled disorder, (KBr${)}_{1\mathrm{\ensuremath{-}}\mathit{x}}$(KCN${)}_{\mathit{x}}$, (NaCl${)}_{1\mathrm{\ensuremath{-}}\mathit{x}}$, (NaCn${)}_{\mathit{x}}$ ${\mathrm{Zr}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$${\mat…