Writers: A. Mesquita, A. Michalowicz, V. R. Mastelaro
Keywords: Dielectric Permittivity; Ferroeletrics; Lead Zirconate Titanate; PCZT; PSZT; PZT; XANES
Abstract: This paper reports the influence of Sr- and Ca-substitution on the structural and ferroelectric properties of Pb1–x Srx Zr 0.40Ti0.60O3 (PSZT) and Pb1–x Ca x Zr 0.40Ti0.60O3 (PCZT) ceramic systems. The dielectric measurements show that these substitutions cause a diffuse behavior in the dielectric permittivity curves for all samples. According to the X-ray absorption near-edge structure (XANES) spectra collected at Ti K- and LIII -edge, when Pb was replaced by Sr or Ca, a decrease in the local distortion around Ti atoms in the TiO6 octahedron could be observed. The O K-edge XANES spectra also revealed that the hybridization between O 2p and Pb 6sp states decreased as the amount of Sr or Ca atoms increased. Based on these results, it was possible to ascertain that the ferroelectric behavior in PSZT and PCZT samples bears a close correlation to the hybridization weakening between O 2p and Pb 6sp states.