Segregation coefficient of Yb3+ and Yb2+ ions in YbF3 doped BaF2 crystals

BaF2:0.17 mol%YbF3 crystal was grown using the conventional Bridgman technique. The optical absorption spectra reveal the existence of both Yb2+ and Yb3+ ions with the characteristic bands of the trivalent ions in the near-IR region and of the divalent ions in the UV spectral domain. The concentration distribution of the Yb2+ and Yb3+ ions among the sample was investigated using the optical absorption method. The segregation coefficient of the two types of Yb ions has been determined. From our calculations the segregation coefficient of the Yb3+ ions in BaF2 host is ≈ 0.7, and of the Yb2+ ions is ≈ 0.6.