Study of the features of the magnetic and crystal structures of the BaFe12-X ALXO19 and BaFe12-X GaXO19 substituted hexagonal ferrites

Abstract

The mechanism of formation of polycrystalline hexagonal barium ferrite with diamagnetic substitution with Al and Ga ions is considered. The localization of the dopants (Al and Ga) in hexagonal and spinel blocks is shown. It is found that the main Al-Fe and Ga-Fe substitutions occur in the 12k sublattice. The substitutions break the Fe-O-Fe exchange couples of the 12k sublattice with other sublattices, which leads to the emergence of non-equivalent positions of Fe3+ ions, on the basis of which in the Mössbauer spectra with isomorphic aluminum, 7 sextets are identified and with isomorphic gallium - 6. This leads to a decrease in the magnetic parameters of ferrites, such as specific and residual magnetization, Curie temperature. It is shown that aluminum (x=2.1) entry increases the coercive force, magnetic hardness of the hexagonal ferrite, and gallium (x=0.6) entry lowers the coercive force and magnetic hardness. The angles θ between the magnetic moment and the γ-radiation direction in isotropic substituted hexagonal ferrite polycrystals and foil are determined.