Magnetic coupling behaviors in M-type hexaferrite-perovskite manganese composites

Two different magnetic hysteresis behaviors with and without exchange coupling between magnetic hard M-type Sr-hexaferrite (SrM) and soft perovskite La-Sr manganite (LSMO) could be achieved by controlling the synthesis process routes of the solid-state reaction. Double hysteresis curves without exchange coupling were observed in the composite prepared by calcinations of the mixture of LSMO and SrM powders, while exchange-coupled single hysteresis behavior was obtained in the composite synthesized directly from the initial precursor powders. The possible origins of the difference in the magnetic coupling behavior between the two composites were discussed.