Mn0.7Zn0.3Fe2O4 + BaTiO3 composites: structural, morphological, magnetic, M–E effect and dielectric properties

Abstract

Here in the present investigation, constituent phases of (1 − x)Mn0.7Zn0.3Fe2O4(MZFO) + (x)BaTiO3(BTO) (where x = 0.0, 0.25, 0.50, 0.75 and 1.0) composites have been synthesized by sol–gel auto-ignition route and the composite structure by ceramic route. The XRD analysis ensures that the composite structure consists of both cubic spinel piezomagnetic and perovskite piezoelectric phases. The average crystallite size estimated from Scherrer equation increases from 15.36 to 21.94 nm. The strain induced in individual phases has been investigated by W–H analysis and it is observed that the MZFO phase shows comprehensive type strain while BTO phase shows tensile type strain. Scanning electron micrographs confirm the microstructure of the sample with grain size ranges from 36.006 to 54 nm. Energy dispersive X-ray spectra and elemental color mappings of typical samples (x = 0.0 and 0.75) clearly indicates the phase purity and stoichiometric proportion of the composites. Fourier transform infrared spectra showed five major absorption bands related to stretching vibrations of different kinds of metal ions and oxygen ions. Increasing percentage of BTO phase in the composite reduces the saturation magnetization, remnant magnetization and coercivity. Real and imaginary parts of permittivity show maximum values at lower frequency region and decrease with increase in applied frequency. For the composition (0.25)MZFO–(0.75)BTO, composite shows maximum value of magnetoelectric coupling coefficient (αME = 20.45 mVcm−1 Oe−1). The improved magnetoelectric properties make MZFO–BTO composite applicable for electronic devices.