Synthesis and characterization of (100-x) Ba0.82Sr0.03Ca0.15Zr0.10Ti0.90O3 + (x) Mg0.25Cu0.25Zn0.5Mn0.05Fe1.95O4 composites with improved magnetoelectric voltage coefficient

Abstract

Multiferroic composites having the nominal composition (100-x) [Ba0.82Sr0.03Ca0.15Zr0.10Ti0.90O3] (BSCZTO) + (x) [Mg0.25Cu0.25Zn0.5Mn0.05Fe1.95O4] (MCZMFO) (where x = 5, 10, 20, 40, 60, 80 and 100 wt %) were synthesized by solid state sintering method. The structural, morphological and magnetic properties of the composites were elucidated through X-ray diffractometer (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electronic Microscopy (SEM), Energy Dispersive Analysis of X-ray (EDAX) and vibrating sample magnetometer (VSM). XRD and FTIR analyses revealed that MCZMFO and BSCZTO phases coexist with cubic spinel and tetragonal perovskite structure without interacting with each other. The lattice constant of MCZMFO and BSCZTO phases in the composites increases with increase of MCZMFO phase due to increased inner stress. SEM and EDAX analyses reveal a homogeneous microstructure with uniform dispersion of MCZMFO grains and presence of Mg, Cu, Zn, Mn, Fe, O, Ba, Sr, Ca, Zr and Ti elements respectively. At low frequencies, the dielectric dispersion for x = 80 and 100 wt % composites is due to interfacial polarization emanating from the interface of the two phases. At higher frequencies, the electron hopping does not follow the fast variation of the alternating applied electric field as a consequence the dielectric constant remains constant. The electrical conductivity exhibits that the conduction mechanism is in conformity with electron hopping model. The real part of the initial permeability increases except for x = 20 wt % composites and the peak of Q-factor spreads with the MCZMFO content in the composites. Two semicircular arcs have been observed for x = 80 and 100 wt % (MCZMFO) composites which corresponds to both grain and grain boundary contribution to electrical properties. Electric modulus study reveals the satisfactory polaron hopping and the presence of negligibly small electrode effect contribution. The magnetic properties increases with increase of MCZMFO phase in the composites. The maximum magnetoelectric coupling coefficient is found to be 1.74 V cm−1Oe−1 for x = 20 wt % composites and this value is significantly larger than those reported particulate composite in literature and as well as the close proximity to the theoretical value (2.4 V cm−1Oe−1). This significant large value of magnetoelectric coupling coefficient makes BSCZTO/MCZMFO composites potential candidates for multifunctional devices applications.