Hyperfine interactions and dynamic characteristics of Sn-119 dopant atoms in Ca2Fe2O5

Sn-119 Mossbauer spectra of tin impurity ions located in the bulk of Ca2Fe2 O5 particles have been investigated over the 77-1070 K temperature range. T his study has allowed us to determine the sign of electric field gradient ( EFG) as well as the angle between directions of the main EFG axis and magne tic field induced at Sn-119 nuclei, The values obtained appear to be in a g ood accordance,vith distorted octahedral coordination of Sn-119(4+) ions. A nalysis of the asymmetry of the Sn-119 quadrupole doublet at T > T-N shomed that the mean-square amplitudes of Sn4+ thermal vibrations along the EFG d irection are greater than those in the perpendicular direction. The tempera ture behavior of the Sn-119 spectra is described in terms of the Debye mode l. (C) 2000 Academic Press.