Neutron diffraction structure study of Er and Yb doped YAl3(BO3)4

Neutron diffraction structure study has been performed on YAl₃(BO₃)₄ (YAB), on doped Y_0.88Er_0.12Al₃(BO₃)₄, Y_0.5Er_0.5Al₃(BO₃)₄, Y_0.5Yb_0.5Al₃(BO₃)₄ and on co-doped Y_0.84Er_0.01Yb_0.15Al₃(BO₃)₄ compositions. It was established that the doped compounds are isostructural to YAB. The neutron diffraction pattern have been be fitted in space group R32 using the triple hexagonal Wyckoff notation. Both Er³⁺ and Yb³⁺ ions occupy the Y³⁺ (3a) sites and not the Al³⁺ (9d) sites, as it was suggested previously. The lattice parameters are decreasing with increasing amount of the dopant elements. Slight changes are revealed in the positional parameters and interatomic distances with increasing concentration of the dopant ions. For the co-doped Y_0.84Er_0.01Yb_0.15Al₃(BO₃)₄ the changes are more significant than for the doped YAB compounds with only one type of dopant element, Er or Yb.