Superior electromagnetic properties obtained by enhanced resistivity on multiferroic barium titanate and hexaferrite di-phase composite ceramics

Di-phase multiferroic composite ceramics of 0.9BaTiO3-0.1Ba(1-x)SrxFe12O19 have been successfully prepared using microwave hydrothermal and microwave sintering methods. The mobility is decreased resulting in increased resistivity due to the crystal structure becomes more compact (Sr2+ ionic radius is smaller than Ba2+) after doping Sr2+. The study of dielectric exhibits the tanδ decreasing and ε′ increasing after doping Sr2+. To further study the two relaxation peaks, the activation energy is calculated which originate in the Debye-like relaxation and hopping of electrons between Fe2+/Fe3+, respectively. The P-E loops show slimmer loops as a result of reduced the dielectric loss and conductive leakage loss owing to higher resistivity obtained after doping Sr2+. All the magnetic hysteresis loops present a waisted shape which is attributed to the change of grain size and existence of non-magnetic phase BaTiO3. In summary, the nearly invariable ferromagnetism but enhanced dielectric and ferroelectric properties multiferroic composite ceramics are obtained by doping Sr2+. In addition, the sample of x = 0.6 has the best-integrated performance among all the contents.