Mössbauer and magnetic studies of the phase state of SrFe12O19/La0.9Ca0.1MnO3 composites

The formation of an intermediate phase in SrFe12O19/La0.9Ca0.1MnO3 composites was demonstrated for the first time using only Mössbauer spectroscopy. The SrFe12O19/La0.9Ca0.1MnO3 composite was prepared by the two-stage (sol–gel and hydrothermal) synthesis with varying initial conditions. The X-ray diffraction studies showed that the composite consisted of two phases: well-formed structures of manganite La0.9Ca0.1MnO3 and hexagonal ferrite SrFe12O19. It was found that nanocrystalline La0.9Ca0.1MnO3 particles with size d ≲ 150 nm formed in the composites at the surface of plate-like SrFe12O19 crystallites. The Mössbauer studies showed that the composite contained additional (intermediate) phase La0.9Ca0.1Mn(Fe)O3 that formed at the interface between SrFe12O19 and La0.9Ca0.1MnO3 phases. The intermediate phase concentration increased with the molar content of La0.9Ca0.1MnO3; in this case, the fraction of the surface of SrFe12O19 crystallites coated with La0.9Ca0.1MnO3 increased, which led to the increase in the total area of the interface surface and the intermediate phase concentration.