0.5Na 0.5)TiO 3-0.075BaTiO 3 relaxor ferroelectric ceramics]]>

摘要

AbstractThis work highlights structural and domain evolution, orbital hybridization, and giant strain in the textured [(Bi1/2Na1/2)0.925Ba0.075](Ti0.998Mn0.002)O3(BNT-7.5BT-0.2%Mn) ceramics. The as-sintered textured specimens reveal a predominant tetragonalP4bm(fraction?94.4%) phase with a minor rhombohedralR3c(fraction?1.4%) phase. X-ray absorption spectra indicate reduced hybridization between the O 2pand the Na 3sp/Bi 6sp/Ti3dorbitals, implying decreased atomic bonding due to Mn doping. A mixture of Mn2+, Mn3+, and Mn4+valence states was identified in the ceramic matrix. In-situ electric (E)-field dependent XRD results show a reversibleE-field-induced phase transition, suggesting an ergodic relaxor ferroelectric. AnE-field-induced giant strain of ?0.495% at room temperature is attributed to the oriented relaxor ferroelectricP4bmphase and decreased bonding strength, which facilitate a transition from relaxor to ferroelectric phase. The poled specimen atE?=?60?kV/cm shows a structural transition sequence of tetragonalP4bm?+?rhombohedralR3c→?220°CtetragonalP4bm→?483°Ccubic.Highlights?AnE-field-induced giant strain mechanism in relaxor ferroelectric is proposed.?The poled specimen proposed a structural phase transition sequence during heating.?Electromechanical strain, structural transition, and atomic bond were studied.]]>