Electromagnetic properties of multiferroic magnetoelectric BaTiO3–CoxFe3−xO4 core–shell particles obtained by homogeneous coprecipitation

Electromagnetic properties of multiferroic magnetoelectric core–shell structured BaTiO3–CoxFe3−xO4 composite particles synthesized by homogeneous coprecipitation method were studied. The complex permeability and permittivity of samples prepared with different R values (the molar ratio of FeCl2·4H2O to CoCl2·6H2O, M(FeCl2·4H2O)/M(CoCl2·6 H2O)) during the coprecipitation processes were measured in the frequency range of 2–8 GHz by a network vector analyzer. The result showed that the electromagnetic parameters of BaTiO3–CoxFe3−xO4 core–shell particles could be controlled effectively by adjusting the R value of reaction solution. The increasing R value intensified the interfacial polarization process, leading the ε′ value of BaTiO3–CoxFe3−xO4 core–shell particles to increase and the fluctuation of ε″ curves to become obvious. Meanwhile, the increasing R value enhanced Ms and adjusted the direction of easy magnetization axis, which resulted in the μ′ value of BaTiO3–CoxFe3−xO4 core–shell particles getting increased and the resonance peak of μ″ moving to a higher frequency. The increased complex permeability and permittivity also resulted in an improvement of dielectric and magnetic loss. - Highlights: ► We studied electromagnetic properties of BaTiO3–CoxFe3−xO4 core–shell particles. ► The molar ratio of FeCl2·4H2O to CoCl2·6 H2O(R) controls electromagnetic parameters. ► Interfacial polarization adjusted by R affects ε′ value and the fluctuation of ε″. ► Ms enhanced by increasing R makes the μ′ increase with R value. ► Direction of easy magnetization axis adjusted by R affects the resonance peak of μ″.