Control of electromagnetic properties in substituted M-type hexagonal ferrites

Present paper describes systematic studies of the functional BaFe12-xDIxO19 (DI = Al3+, In3+ 0.1 ≤ x ≤ 1.2) solid solutions. Correlation between the fine atomic structure and intrasublattice Fe3+ - O2− - Fe3+ superexchange interactions were explained using precision neutron powder diffraction and Mossbauer spectroscopy. Critical influence of the diamagnetic Al3+ and In3+ ions on electromagnetic properties in substituted Ba-hexaferrites (M-type) was discussed. Transmission spectra demonstrated a deep minimum in the frequency range 20-65 GHz due to natural ferromagnetic resonance (NFMR). Increase of the Al3+ ions concentration shifted the resonance frequency from 51 GHz to 61 GHz. Increase of the In3+ ions shifted the resonance frequency from 50.5 GHz to 27 GHz. Data of the numerical calculations and experimental results correlates well. It has been demonstrated that external magnetic fields critically influence on electromagnetic properties due to increase of magnetic anisotropy. This opens broad perspectives for practical applications.