Magnetic field induced polarization and magnetoelectric effect in Na0.5Bi0.5TiO3-Co0.75Zn0.25Cr0.2Fe1.8O4 multiferroic composite

Multiferroic composites of Zn-Cr substituted cobalt ferrite (Co_0.75Zn_0.25Cr_0.2Fe_1.8O₄) (CZCFO) nanoparticles and lead-free piezoelectric sodium bismuth titanate Na_0.5Bi_0.5TiO₃ (NBT) having composition (1 - x) Na_0.5Bi_0.5TiO₃ + (x)Co_0.75Zn_0.25Cr_0.2Fe_1.8O₄ (x = 0.0, 0.25, 0.5, 0.75, 1.0) were investigated in this study. Ferromagnetic-CZCFO and ferroelectric-NBT phases were synthesized via sol-gel auto combustion route and solid-state reaction methods respectively. The structural properties of composite materials were studied using X-ray diffraction (XRD) technique. Intense and sharp peaks observed in XRD patterns confirm that both the phases are well crystalline in nature. Two separate phases of CZCFO and NBT are present in composite material without any impurity or chemical reaction among them. The morphology of prepared samples was studied via scanning electron microscopy confirming that composite materials are well-densified and homogenous grain size distribution. The magnetic hysteresis loops of multiferroic composite were investigated by using vibrating sample magnetometer at room temperature. The lead free multiferroic composite exhibiting a large converse magneto-electric (ME) effect at room temperature. The maximum value of ME coefficient (α_ME = 7.92 kV/cm) is obtained at x = 0.50. Furthermore, electrical properties of nanocomposite material were studied by P-E hysteresis loop and dielectric measurements at room temperature.