Structural refinement, investigation of dielectric and magnetic properties of NBT doped BaFe12O19 novel composite system

Currently, it is crucial to develop lead-free multifunctional multiferroic composites for lesser environmental hazards, low cost, and diversified potential applications. We have developed a novel lead free ferrite-ferroelectric composite system with composition (1-x)Na0.5Bi0.5TiO3-(x)BaFe12O19; (x = 0.2, 0.5, 0.8 and 1) via solid-state reaction route. The XRD analysis followed by Rietveld Refinement confirmed the formation of hybrid composites with both ferroelectric and ferromagnetic phases. SEM with EDX and HRTEM used to study the morphology and compositional analysis. The slight changes in cell volume, axial ratio (c/a), bond distances and bond angles confirm lattice-distortion. Low frequency and higher temperature dispersion is observed for both dielectric constant and tangent loss. Moreover, dielectric constant increases up to x = 0.5 and then decreases while tangent loss increases with the addition of BaM. The ac conductivity was found to be increased on increasing frequency, temperature and hexaferrite content in the composites. The dc conductivity curve was found to follow the Arrhenius plot. Room temperature multiferroism is confirmed by P-E, M - H loop and magnetoelectric measurements. Anisotropy constant and field were evaluated from fitted high field M - H loop using the law of approach to saturation (LAS) and both of these and other magnetic parameters found to increase with hexaferrite content. It is observed that P-s and P-r increases with BaM up to x = 0.5 and then decreases. The magnetoelectric coupling coefficient is found to show a maximum value of 2.29 mV/cm.Oe for x = 0.2 sample. (C) 2020 Elsevier B.V. All rights reserved.