Effect of sintering temperature on magnetoelectric properties of Co 0.8 Cu 0.2 Fe 2 O 4 @(Pb 0.95 La 0.05 )(Zr 0.86 Ti 0.14 )O 3 ceramics

The effects of sintering temperature on the dielectric, ferroelectric, and magnetic performance of Co 0.8 Cu 0.2 Fe 2 O 4 @(Pb 0.95 La 0.05 )(Zr 0.86 Ti 0.14 )O 3 (CCFO@PLZT) composite ceramics with core–shell structure were investigated. The X-ray diffraction results confirmed the bi-phase structure of the composites, with insufficient sintering temperature and inadequate reaction leading to the presence of Pb 2 O 3 and ZrO 2 . Transmission electron microscope images showed that the core–shell structure was prepared, and the scanning electron microscope images showed that the average grain size of the ceramic samples increased with the increase of the sintering temperature. The dielectric constant does not change linearly as the sintering temperature rises, but tends to increase and then decrease, which could be owing to the fact the crystallinity of impurities increases, affecting their dielectric properties. The dispersion indices were 1.58, 1.64, 1.60, 1.61, and 1.70 with increasing temperature, indicating that the relaxation of CCFO@PLZT ceramics was enhanced. The residual polarization intensity ( P r ) of CCFO@PLZT ceramics increased first and then decreased with increasing sintering temperature, reaching a maximum value of P r ~ 1.849 μC/cm 2 at 1050 °C, but this may be caused by the excessive leakage current. Grain growth, density reduction and partial reduction of Fe 3+ ions to Fe 2+ ions lead to a decrease in saturation magnetization intensity ( M s ), residual magnetization intensity ( M r ) and coercivity ( H c ) with the increase of sintering temperature.