Crystal growth and properties of (Lu,Y) 3Al 5O 12

LuYAG [(Lu,Y) ₃Al ₅O ₁₂] single crystals have been grown by means of the Czochralski method. The solidification points of LuYAG ranged from 2010°C for Lu ₃Al ₅O ₁₂ to 1930°C for Y ₃Al ₅O ₁₂. Lattice parameters of LuYAG changed linearly with variations in composition from 11.9164(4) Å for Y ₃Al ₅O ₁₂ to 12.0075(3) Å for Y ₃Al ₅O ₁₂. The effective segregation coefficients k_eff, experimentally determined from the lattice parameters, show that compositional segregation of Y atoms proceeds with increasing Lu content. The heat capacity, heat diffusivity, and thermal conductivity of Y ₃Al ₅O ₁₂, Lu ₂YAl ₅O ₁₂, Lu _1.5Y _1.5Al ₅O ₁₂, LuY ₂Al ₅O ₁₂ and Y ₃Al ₅O ₁₂ were also measured. The two latter properties exhibit minima near the equimolar solid solution composition. Refractive indices, determined by the minimum deviation method, vary smoothly between 0.40 and 1.97 μm wavelengths and permit derivation of the Sellmeier constants.