Structural, magnetic, dielectric and electrical properties of Ba0.77Ca0.23TiO3–Ni0.6Zn0.25La0.15Fe2O4 multiferroic composites.

In this work, multiferroic composites of (1−x) Ba_0.77Ca_0.23TiO₃ + x Ni_0.6Zn_0.25La_0.15Fe₂O₄ (x = 0.0, 0.1, 0.2, 0.3, 0.5, 0.7, 0.9 and 1.0) have been synthesized using solid-state reaction method and their different properties have been systematically investigated. X-ray diffraction (XRD) studies reveal the formation of cubic structure for perovskite and cubic spinel structure for ferrite phases with crystallite sizes in the range of 17.79–28.21 nm. Scanning electron microscope (SEM) analyses show that the boundaries between Ca-doped BaTiO₃ (BCT) and La-doped Ni-Zn ferrite (NZLFO) phases are very clear which indicates small atomic diffusion. The average grain size was found to vary from 2.27 to 0.83 µm with increasing ferrite content. The M-H hysteresis loops obtained from vibrating sample magnetometer (VSM) measurements show as the content of the ferrite phase is increased the saturation magnetization and the remnant magnetization increase but the coercive field and thereby the magneto crystalline anisotropy energy decreases. High dielectric constant values are observed at low frequencies but it decreases with the frequency up to about 7 MHz and beyond which becomes frequency-independent. AC conductivity of the composites derived from dielectric constant and loss tangent values can be described by the hopping mechanism. [ABSTRACT FROM AUTHOR]