Single-crystal elastic properties of (Y,Yb)3Al5O12

Brillouin scattering experiments were performed on single crystals in the solid solution series Y3Al5O12–Yb3Al5O12 (with XYb=0,0.39,0.81,1). Elastic stiffness tensor, bulk modulus K, Young’s modulus, and shear modulus were determined, which were previously only known for the yttrium end member. In our experiments, K increased by ∼4% from Y3Al5O12 to Yb3Al5O12, whereas shear modulus and Young’s modulus were insensitive to compositional change. To complement our experimental results, we performed ab initio density functional theory (DFT) simulations for Y3Al5O12 and classical interatomic potential calculations for Yb3Al5O12. While the experimental results are in good agreement with our DFT calculations, the results from classical potential calculations differ significantly from experiments.