Structural, microstructural, electromagnetic and magnetoelectric properties of (1 − y) [Ba0.85Ca0.15Zr0.1Ti0.9O3] + (y) [Ni0.92Co0.03Mn0.05Cu0.05Fe1.95−xAlxO4] composites

In the present study, polycrystalline (1 − y) [Ba_0.85Ca_0.15Zr_0.1Ti_0.9O₃] (BCZTO) + (y) [Ni_0.92Co_0.03Mn_0.05Cu_0.05Fe_1.95−xAl_xO₄] (NCMCFAl_xO) (where x = 0, 0.1, 0.3, 0.5, 0.7, 0.9 and y = 0.5) composites were synthesized via solid state reaction route. The samples were characterized through the standard techniques. X-ray diffraction (XRD) analysis revealed the successful formation of the BCZTO-NCMCFAl_xO composites without any extra phases and diffusion. The lattice parameter of BCZTO and NCMCFAl_xO decreases as the concentration of Al³⁺ increases. SEM analysis reveals that the microstructure exhibits nonuniform grain size distribution with Al³⁺ concentration. The dispersion of dielectric constant is well consistent with Maxwell-Wagner interfacial polarization and the dielectric constant decreases as the concentration of Al³⁺ ions increases due to the difference of ionic radii. The electrical conductivity is due to the small polaron hopping according to Austin-Mott model. The decrement in saturation magnetization with increasing Al³⁺ concentration because exchange interactions is weakened through the substitution of Fe³⁺ by Al³⁺ ions. Permeability decreases with Al³⁺ concentration and exhibits good frequency stability over the entire measured frequency domain. The magnetoelectric coupling coefficient decreases as the concentration of Al³⁺ increases at both sintering temperatures which is due to the variation of grain size. The maximum magnetoelectric voltage coefficient of 0.72 V Oe⁻¹ cm⁻¹ was obtained for the pristine composite at 1373 K. [ABSTRACT FROM AUTHOR]