Exploring the coupling effect of ferromagnetic, Co0.8Zn0.2Fe2O4 with the ferroelectric, Ba0.5La0.5TiO3 at different concentrations in composite multiferroics

Abstract

The solid-state reaction method is followed to fabricate multiferroic particulate composites, (1-x) Ba0.5La0.5TiO3 + (x) Co0.8Zn0.2Fe2O4 (x = 0.0, 0.1, 0.3, 0.5, 0.7, 0.9, 1.0). X-ray diffraction patterns reflect the coexistence of the constituent phases in the composites after 4 h of sintering at 1200 °C. Cubic structures of both ferroelectric and ferrite phases confirmed from Rietveld refinement are distinctively dominant. The Fourier Transform Infrared (FTIR) spectrum confirms the characteristic vibration bonds of Co-ferrite, Zn-ferrite, and Ti-O. A slight variation of lattice parameters is observed with the increasing ferrite concentration. Bulk density reveals the inverse behavior of theoretical density. The obtained average grain size varies from 1.308 µm to 3.046 µm. All the composites have good ferromagnetic properties confirmed by hysteresis loops. The coercive field at x = 0.5 is 297.98 Oe, dramatically higher than other concentrations. The real part of permeability (μi′) gradually increases with increasing ferrite content as per the sum rule of the mixture. To investigate the electric properties of the samples, the dielectric constant (ε′) and loss tangent (tanδ) are measured in the frequency range of 100 Hz to 100 MHz. The dielectric constant (ε′) decreases at first and after x = 0.3, it begins to increase with further addition of the ferrite phase. The maximum dielectric constant (ε′) is 1092.08 at x = 0.9. The dielectric constant (ε′) and loss tangent (tanδ) display Maxwell-Wagner interfacial polarization and reduce from low to high frequency. All of the samples appear to be highly resistive indicating the reduction of leakage current. The dielectric constant (ε′) and resistivity show the opposite trend. P-E hysteresis loops indicate para-electric to ferroelectric transition.