Electromagnetic properties of multiferroic magnetoelectric BaTiO_3-Co_xFe_(3-x)O_4 core-shell particles obtained by homogeneous coprecipitation

摘要

Electromagnetic properties of multiferroic magnetoelectric core-shell structured BaTiO_3-Co_xFe_(3-x)O_4 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 FeCl_2·4H_2O to CoCl_2·6H_2O, M(FeCl_2·4H_2O)/M(CoCl_2·6 H_2O)) 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 BaTiO_3-Co_xFe_(3-x)O_4 core-shell particles could be controlled effectively by adjusting the J? value of reaction solution. The increasing R value intensified the interfacial polarization process, leading the ε' value of BaTiO_3-Co_xFe_(3-x)O_4 core-shell particles to increase and the fluctuation of ε" curves to become obvious. Meanwhile, the increasing R value enhanced M_s and adjusted the direction of easy magnetization axis, which resulted in the μ' value of BaTiO_3-Co_xFe_(3-x)O_4 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.