Preparation and Investigations of the Magnetoelectric Properties of (Ni_0.5Zn_0.5Fe₂O₄)_x [(Na_0.5Bi_0.5)_0.7Ba_0.3TiO₃]_1–x (x = 0.3, 0.5) Nanocomposite Ceramics for Magnetic Field Sensor Applications

A multiferroic nanocomposite was derived by considering Ni_0.5Zn_0.5Fe₂O₄ (NZFO) and Ba-doped Na_0.5Bi_0.5TiO₃ (NBBTO) as the constituent components. Nanoparticles of (Na_0.5Bi_0.5)_0.7Ba_0.3TiO₃ synthesized by the sol–gel technique were successfully incorporated into NZFO during its preparation. For this experiment, two distinct stoichiometric ratios were taken: (NZFO)_0.3(NBBTO)_0.7 (NZFO-NBBTO-1) and (NZFO)_0.5(NBBTO)_0.5 (NZFO-NBBTO-2). The X-ray diffractograms were subjected to Rietveld refinement, confirming the desired phase formation without any impurity. Images captured by field-emission scanning electron microscopy showed that particles are uniformly scattered with distinct spherical morphology. The lack of impurity elements was verified by energy-dispersive X-ray spectroscopy (EDAX), and EDAX mapping showed that the constituent elements were distributed uniformly. The magnetic moment variation from 300 to 50 K was analyzed to identify magnetic phases in the composites. The presence of nearly saturated loops was revealed in both composites by the zero-field-cooled and field-cooled magnetization data as a function of the temperature and magnetization versus field loops, as recorded by vibrating sample magnetometry (VSM). The maximum magnetization was observed to be 16.76 emu/g for NZFO-NBBTO-1 and 22.45 emu/g for NZFO-NBBTO-2 at 300 K. At 300 K, both composites exhibited good dielectric properties, with a dielectric strength of ∼320 and a low loss of ∼0.5. Direct observation of the ferroelectric loop indicated that NZFO-NBBTO-1 exhibited better ferroelectricity (P_max ∼0.018 μc/cm²) compared to NZFO-NBBTO-2 (P_max ∼0.01 μc/cm²). The magnetocapacitance coefficient was also higher in NZFO-NBBTO-1 (∼4%) than in NZFO-NBBTO-2 (∼3%). In general, the findings indicate that NZFO-NBBTO-1 shows great promise as a potential candidate for a magnetoelectric multiferroic material that could be used for the development of magnetic field sensors, spintronic devices, sensors, microelectronic devices, actuators, and electronic memory devices.