Structures and fluorescence of nanocrystallines MSO4:xSm3+ (M = Ca, Sr, Ba; x=0.001 ∼ 0.005) with γ-ray irradiation

A series of nanocrystallines MSO4:xSm(3+) M = Ca, Sr, Ba; x = 0.001 similar to 0.005) were prepared by a co-precipitation method. Their crystal structures and fluorescence with and without gamma-ray irradiation are compared. It was found that their crystal structures have not changed and their lattice parameters of nanocrystals both with and without gamma-ray irradiation were increased with the augmentation of the content of doped Sm3+; however, their lattice parameters of the same nanocrystals with irradiation become smaller than that without irradiation. The characteristic emissions of both Sm3+ ion and Sm2+ ion are observed in the same nanocrystals after gamma-ray irradiation. The differences in their crystal structures and luminescent properties are also discussed. (C) 2000 Elsevier Science B.V. All rights reserved.