The Dielectric, Magnetic, and Ferroelectric Analysis of xNi0.5Co0.5Fe2O4:(1 − x)PANI Multiferroic Composites

Different compositions of the nanocomposite lead-free multiferroic systems are fabricated by employing piezoelectric polyaniline (PANI) and magnetostrictive Ni0.5Co0.5Fe2O4 (NCF) by varying the NCF weight fraction. The current work reports the synthesis of xNCF:(1-x)PANI hybrid composite systems prepared via the physical blending method. X-ray powder diffraction (XRD) exhibits the presence of both; a polymeric amorphous phase of PANI (matrix) and a crystalline phase of inverse spinel ferrite NCF (filler) in the composites. The microstructure analysis along with the elemental composition of the samples are studied via Field emission scanning electron microscopy (FESEM) and Energy Dispersive X-ray Analysis (EDAX) respectively. Here, frequency-dependent dielectric permittivity exhibits percolation-type behavior where permittivity (ε′) attains a peak at a critical weight fraction (x = 0.3). The magnetic properties for the particular stoichiometric concentration (x = 0.3) of the composite exhibit a large enhancement in the saturation magnetization (Ms) of 75.22 emu g−1, while maintaining the soft ferromagnetism in the nanocomposite system. The switching behavior of electrical polarization in composite systems exhibits strong temperature dependence with a ferroelectric loop that appears to persist at even low temperatures (5 K). The remnant electrical polarization (Pr) is found to decrease with the increase in ferrite (NCF) concentration. Hence, the developed composite system at the high electric field exhibits both ferroelectric and ferromagnetic characteristics without significant conductive losses making it suitable for potential multiferroic and capacitor applications.