HYPERFINE INTERACTIONS AND SITE POPULATION IN THE SPINEL COMPOUNDS CAXCO1-XFE2O4

Mossbauer spectra of the spinel series CaxCo1-xFe2O4, with x = 0.0, 0. 05 and 0.10, have been collected between 80 and 300 K and in an applie d field of 6 T at 4.2 K. From the shape-independent hyperfine field di stribution fits of the external field spectra, and from the binomial d istribution fits of the temperature-dependent spectra, the hyperfine f ield and the center shift could be unambiguously assigned to octahedra lly and tetrahedrally coordinated ferric ions. The importance of the a pplication of an external field in conjunction with a reasonable physi cal model to obtain a correct assignment of hyperfine parameters to a specific site is demonstrated.