Synthesis and characterization of Fe3+-modified PLZT ferroelectrics

Fe³⁺-modified nanocrystalline PLZT, i.e., Pb_0.92[La_1–zFe_z]_0.08[Zr_0.60Ti_0.40]_0.98O₃ (PLFZT) (z=0.0, 0.3, 0.6, 0.9, 1) materials were synthesized by a high-temperature solid-state reaction technique. X-ray studies of the compounds confirmed the formation of single-phase, ultrafine (nano-sized) and homogeneous materials. Microstructural scanning electron microscopy (SEM) study shows the uniform distribution of smaller grains on the surface of the samples. Detailed dielectric studies of the compounds as a function of temperature (30–450 °C) show that the broadening of the permittivity peak and transition temperature depends on Fe³⁺-ion concentration. Analysis of diffuseness () of the broadened dielectric peaks of the materials gave its value between 1 and 2, indicating the different degrees of substitutional disorder in the system. The increase in Fe³⁺-substitution at the La-site of PLZT shows many interesting and unusual dielectric relaxor behaviors of the compounds. The transition temperature T_c of PLZT (8/60/40) ferroelectric shifts towards a higher temperature region on increasing Fe³⁺ concentration. The variation of d.c. and a.c. electrical conductivity of the material with temperature shows its semiconducting behavior; and hence the materials can be used for some electronic devices.