Structural, Dielectric, and Magnetic Properties of Lead Zirconate Titanate–Cobalt Ferrite Magnetoelectric Composites

Abstract

In this work, the magnetoelectric composites (1 – x)PbZr0.52Ti0.48O3–xCoFe2O4 ((1 – x)PZT–xCFO) have been synthesized using the combination of sol-gel (for PZT ceramic) and the solid-state (for CFO material) methods. X-ray powder diffraction results and Rietveld refinement have shown that the PZT compound crystallizes in two tetragonal and rhombohedral structures with P4mm and R3m space groups, respectively, while the CFO material has shown a spinel cubic structure with Fd3m space group. The (1 – x)PZT–xCFO composites, for x = 0.10 to 0.50, have been fitted and matched very well to the phases corresponding to PZT and CFO materials. The effect of sintering temperature on the structural and dielectric properties of these composites has been also studied (for x = 0.20). It has been found that the phase is stable for 900°C for 4 h while for 1000 and 1100°C we obtain many secondary phases. On the other hand, the pellet sintered at 900°C shows a low dielectric permittivity value and high relaxation behavior. The scanning electron micrographs (SEM) reveal multigrain agglomerations for all the samples and the grain size is maximal (about 2 µm) for x = 0.10 of CFO content and minimal (about 0.7 µm) for pure CFO. The dielectric properties of the composite samples have been also investigated as a function of temperature and showed one phase transition at 410°C for PZT ceramic. This phase transition has shifted to the lower temperature and present a relaxation phenomenon with the increase of CFO content. The dielectric permittivity decreases with the increase of CFO rate related to the CFO ceramic which has a low dielectric permittivity value. The magnetic properties of these magnetoelectric (ME) composites have been also studied by measuring the magnetization as a function of temperature. The obtained results show one maximum of around 427°C related to the phase transition temperature of CFO. In addition, the magnetization value is found to increase when CFO content increases indicating an intrinsic ME coupling.