Thermophysical Characteristics of Single Crystals of Ba1 –x–yYbxRyF2 +x+y (R = Tm, Ho) Solid Solutions.

Single crystals of Ba1 –x–yYbxRyF2 +x+y (R = Tm, Ho) solid solutions have been grown by the Bridgman technique in vacuum using a CF4 fluorination atmosphere. We have measured their thermal conductivity in the range 50–300 K and their refractive index from the visible to IR spectral region. As the ytterbium content increases from 2 to 14 mol %, the room-temperature thermal conductivity of the solid solutions with R = Tm and Ho decreases from 3.39 to 1.18 and from 3.11 to 1.18 W/(m K), respectively. Raising the holmium and thulium content of the solid solutions leads to a gradual increase in their refractive index, and it gradually decreases with increasing wavelength. [ABSTRACT FROM AUTHOR]