Effect of BaTiO3 phase on frequency dispersion characteristics of Mg0.48Cu0.12Zn0.4Fe2O4 + BaTiO3 nanocomposites

Multiferroic nanocomposites of ferrite and ferroelectric phases with systematically varying composition (100-x) Mg0.48Cu0.12Zn0.4Fe2O4 + xBaTiO(3) (MCZBT) (where, x = 0, 20, 40, 50, 60, 80, 100 mol%) were prepared for the first time by mechanical milling and sintering method. The presence of ferrite and ferroelectric phases in nanocomposite samples were confirmed by X-ray diffraction (XRD) while microstructural characterization was carried out by scanning electron microscopy (SEM). The average grain size, from SEM, was found to be in the range 80 nm for ferrite and 86 nm for BaTiO3 nanopowders. The complex permittivity and the complex permeability variations as a function of frequency in the range 100 kHz - 1.8 GHz, were investigated using LCR meter and Impedance analyzer. The resonance and relaxation phenomena were observed by all the samples around 1.18 GHz from the permittivity studies. From the studies of microwave absorbing properties in X-band (8-12 GHz) frequency region, it was found that the minimum reflection loss of -24.61 dB with bandwidth of 0.38 GHz was obtained by sample with 20% ferroelectric phase. The studies on reflection loss and transmission loss indicated that the effective absorption of incident microwave was found to be above 80% and the composite sample with 80% of ferroelectric phase absorbed more than 91% of the incident wave. The results suggested that the present sample materials can be used for making microwave shielding devises for EMI applications.