Magneto-dielectric properties studies of the matrix composite [SrFe12O19(SFO)1-X - BiFeO3(BFO)X]

The effects of different BiFeO3 (BFO) additions (0, 20, 40, 60 and 80 wt%) on the SrFe12O19 hexaferrite ceramic matrix (SFO) have been studied by Complex Impedance Spectroscopy (CIS), Mossbauer spectroscopy, magnetic hysteresis and X-Ray Diffraction (XRD) analysis. The solid state reaction method was used for the production of the SFO and BFO, the phase formation was confirmed by the XRD and Rietveld refinement, where the obtained fitting presented an effective refinement. The diffractogram for BFO-SFO composites presented all peaks in agreement with the BFO and SFO phases. The thermo-activated process was studied by the CIS and the Arrhenius equation in the composite series of BFO-SFO with SFO presenting higher values of activation energy between the analyzed samples and the frequency and temperature range studied was 1-10 MHz and 160 degrees C to 300 degrees C, respectively. The addition of BFO in the SFO ceramic matrix lead to an improvement of the thermal-stability of the composite, where a signal inversion of Temperature Coefficient of Capacitance (TCC), in the composites, was observed. The Nyquist plots showed the presence of a semicircle that was fitted by an equivalent circuit model using R -CPE association, showing the same profile in all samples. The Mossbauer spectrum of the composites demonstrate the typical five Fe3site for M-type hexagonal ferrites even after the addition of BFO in a ceramic matrix. The addition of BFO in the formation of composites, with SFO, showed interesting results in the radio frequency range and presented magnetic properties that can be explored in applications in the area of telecommunications, medicine and military industry. (C) 2017 Elsevier B. V. All rights reserved.