Magnetoelectric Response in Multiferroic SrFe(12)O(19) Ceramics

We report here realization of ferroelectricity, ferromagnetism and magnetocapacitance effect in singleSrFe(12)O(19)ceramic at room temperature. The ceramics demonstrate a saturated polarization hysteresis loop, two nonlinear I-V peaks and large anomaly of dielectric constant near Curie temperature, which confirm the intrinsic ferroelectricity of SrFe(12)O(19) ceramicswith subsequent heat-treatment in O(2)atmosphere. The remnant polarization of the SrFe(12)O(19) ceramic is estimated to be 103μC/cm(2). The ceramic also exhibits strong ferromagnetic characterization, the coercive field and remnant magnetic moment are 6192Oe and 35.8emu/g, respectively. Subsequent annealing SrFe(12)O(19) ceramics in O(2) plays a key role on revealing its intrinsic ferroelectricity and improving the ferromagnetism through transforming Fe(2+) into Fe(3+). By applying a magnetic field, the capacitance demonstrates remarkable change along with B field, the maximum rate of change in ε (Δε(B)/ε(0)) is 1174%, which reflects a giant magnetocapacitance effect in SrFe(12)O(19). XPS and molecular magnetic moment measurements confirmed the transformation of Fe(2+) into Fe(3+) and removal of oxygen vacancies upon O(2) heat treatment. These combined functional responses in SrFe(12)O(19) ceramics opens substantial possibilities for applications in novel electric devices.