Cation distribution in bismuth-doped M-type barium hexaferrite

Mössbauer studies were conducted on Bi-doped barium ferrites BaFe12–xBixO19 (x = 0, 0.1, 0.2, 0.3, 0.4, and 0.6) with special attention paid to the behavior of the line widths in the Mössbauer sextets. Assuming that the broadening of the line widths in the various sextets is due to increases in the fluctuations in the hyperfine field (acting on a Fe ion in given site) caused by the introduction of the Bi ions into the neighboring Fe sites, the observed broadening of the lines belonging to the 4fvi and 4e patterns indicated that the impurity ions were entering into the 4e and 4fvi sites. The initial decrease in Ms would arise if the Bi ions first substituted in the 4fvi and then into the 4e sites as more Bi is added.