Sublattice magnetization and cation distribution in BaMg2Fe16O27(Mg2W) ferrite

Mössbauer measurements were carried out in compound BaMg
2
Fe
16
O
27
(Mg
2
W) by utilizing both polycrystalline and single-crystal samples. The resonant γ-absorption spectra have been measured with the absorbers at temperatures of 85 to 800°K and in some cases in the presence of a 15-kOe external magnetic field. The values of the hyperfine magnetic fields H
hf
at the Fe
⁵⁷
nuclei in the different sublattices as functions of temperature have been measured. By fitting the curve of the saturation magnetization σ versus temperature, the cation distribution over the available lattice sites has been deduced. From the value of σ extrapolated at 0°K, it turns out that the number of Bohr magnetons
(n_{B})W
per elementary cell is higher than the value obtained by adding the corresponding values for the
S
and
M
structures. The Curie temperature of the compounds has also been measured and is equal to (440 ± 5)°C.