Enhanced magneto-electric properties and magnetodielectric effect in lead-free (1-x)0.94Na0.5Bi0.5TiO3-0.06BaTiO3-x CoFe2O4 particulate composites

The lead-free magnetoelectric particulate composites (1-x)0.94Na(0.5)Bi(0.5)TiO(3)-0.06BaTiO(3)-x CoFe2O4(where, x = 0, 0.15, 0.25, 0.35, 0.45) were synthesized by the solid-state sintering technique. The coexistence of piezoelectric 0.94Na(0.5)Bi(0.5)TiO(3)-0.06BaTiO(3) (NBBT) and ferromagnetic CoFe2O4 (CFO) phases were con-firmedby structural studies. The average crystallite size and the strain produced in the composites between the interface of different phases were estimated using Williamson-Hall method. The microstructural analysis indicates that the closely dense-packed CFO grains are distributed in the NBBT matrix. The ferroelectric nature of the composites was confirmed by the polarization versus electric field hysteresis loop and found to decrease with CFO content, which is attributed to the conducting nature of CFO. The observed values of saturation (M-s), remanent (M-r) magnetization, and magnetic moment (mB) in the composites are 28.46 emu/gm, 5.01 emu/gm and 1.13 mu(B), respectively for the higher CFO content. The dielectric relaxation phenomenain the composites have been observed, and the enhanced dielectric constant (epsilon') is explained based on the electron hopping mechanism. All composites exhibit a relax or nature which is described by the Vogel-Fulcher relation. The magnetoelectric coupling is estimated in the composites indirectly by measuring the relative change in the dielectric constant in the presence of the external magnetic field. The estimated values of magneto-capacitance at 1 kHz frequency for 25 and 35 mol% are similar to - 5.5 and similar to - 6%, respectively, which indicate that these materials can be useful for magneto-dielectric based devices applications.(C) 2021 Elsevier B.V. All rights reserved.

Automated summary

Lead-free magnetoelectric particulate composites were successfully synthesized using the solid-state sintering technique, and the coexistence of piezoelectric and ferromagnetic phases was confirmed. These composites showed excellent magnetoelectric coupling properties and dielectric characteristics, demonstrating potential for applications in magneto-dielectric devices.