Local structure and hybridization states in Ba0.9Ca0.1Ti1−xZrxO3 ceramic compounds: Correlation with a normal or relaxor ferroelectric character. (1st February 2015)

• Record Type: Journal Article
• Authors: Mastelaro, V.R.; Favarim, H.R.; Mesquita, A.; Michalowicz, A.; Moscovici, J.; Eiras, J.A.
• Is Part Of: Acta materialia. Volume 84(2015)
• Page Start: 164
• Page End: 171
• Publication Date: 2015-02-01
• Subjects: Ferroelectrics -- Relaxors -- Lead-free -- Hybridization -- XAS; Materials -- Periodicals; Materials science -- Periodicals; Materials -- Mechanical properties -- Periodicals; Metallurgy -- Periodicals; Chemistry, Inorganic -- Periodicals; 620.112
• DOI: 10.1016/j.actamat.2014.10.059
• Languages: English
• ISSNs: 1359-6454

Abstract

Abstract: This paper reports on a multi-edge X-ray absorption analysis to elucidate how the substitution of Ti 4+ by Zr 4+ ions acts on the local order structure and on the O 2 p hybridization states of Ba0.9 Ca0.1 Ti1− x Zr x O3 (BCZT) lead-free ceramic compounds, inducing a ferroelectric evolution from a normal to a relaxor character. Ti, Ba, Zr and O X-ray absorption spectra were measured to probe the local and electronic structure of BCZT samples that exhibit a normal ( x < 0.18) or relaxor ( x ⩾ 0.18) ferroelectric character. X-ray absorption near edge structure results show that the local symmetry and distortion of TiO6, ZrO6 and BaO12 units are not significantly affected by the Ti/Zr ratio, the ferroelectric character or the long-range order symmetry. The assignment of the ab initio density of states associated with the O K-edge enabled a correlation between the decrease in the hybridization between O 2 p and Ti 3 d states and the ferroelectric character evolution of the BCZT samples. The hybridization states in the ferroelectric relaxor samples exhibit a more symmetric spatial configuration, as occurs with long-range symmetry.