Structure, magnetic, and electrodynamic properties of SrIn_xFe_12-xO₄/Ni_0.5Zn_0.5Fe₂O₄ composites at low temperature

Exchange-coupled hard–soft bi-magnetic ferrites can be used as isolators, microwave absorption materials, filters, hyperthermia materials, and biosensors with improved energy properties. The nanocomposites with the chemical composition SrIn_xFe_12-xO₄/Ni_0.5Zn₀₅Fe₂O₄ (where x varies from 0.00 to 0.04) have the advantages of both materials: spinel and hexaferrite. The combination of Sr-hexaferrate with spinel ferrite results in proximity effects, reversal of magnetization in two stages, and blocking temperatures that can be tuned in bi-magnetic hard and soft ferrites. It was found an anomalius kink in the hysteresis loops and two peaks in the switching field distribution at x ≤ 0.02. The exchange interaction on the surfaces of hard and soft nanoparticles explains the behavior of the magnetic characteristics.