title: Defect Engineering of Lead-Free Piezoelectrics with High Piezoelectric Properties and Temperature-Stability.
abstract: The high piezoelectricity of ABO3-type lead-free piezoelectric materials can be achieved with the help of either morphotropic phase boundary (MPB) or polymorphic phase transition (PPT). Here, we propose a new defect engineering route to the excellent piezoelectric properties, in which doped smaller acceptor and donor ions substituting bivalent A-sites are utilized to bring local lattice distortion and lower symmetry. A concrete paradigm is presented, (Li-Al) codoped BaTiO3 perovskite, that exhibits a largely thermo-stable piezoelectric constant (>300 pC/N) and huge mechanical quality factor (>2000). A systematic analysis including theoretical analysis and simulation results indicates that the Li(+) and Al(3+) ions are inclined to occupy the neighboring A-sites in the lattice and constitute a defect dipole (ionic pairs). The defect dipoles possess a kind of dipole moment which tends to align directionally after thermo-electric treatment. A mechanism related to the defect symmetry principle, phase transition, and defect migration is proposed to explain the outstanding piezoelectric properties. The present study opens a new development window for excellent piezoelectricity and provides a promising route to the potential utilization of lead-free piezoelectrics in high power applications.
authors.affiliation: School of Materials Science and Engineering, Harbin Institute of Technology , Harbin 150001, P. R. China.|Key Laboratory of Engineering Dielectrics and Its Application, Ministry of Education, Harbin University of Science and Technology , Harbin 150080, P. R. China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Feng
authors.affiliation: School of Materials Science and Engineering, Harbin Institute of Technology , Harbin 150001, P. R. China.|National Key Laboratory of Science and Technology on Precision Heat Processing of Metals, Harbin Institute of Technology , Harbin 150001, P. R. China.
authors.forename: Wei-Li
authors.initials: WL
authors.lastname: Li
authors.affiliation: School of Materials Science and Engineering, Harbin Institute of Technology , Harbin 150001, P. R. China.
authors.forename: Dan
authors.initials: D
authors.lastname: Xu
authors.affiliation: School of Materials Science and Engineering, Harbin Institute of Technology , Harbin 150001, P. R. China.
authors.forename: Yu-Long
authors.initials: YL
authors.lastname: Qiao
authors.affiliation: School of Materials Science and Engineering, Harbin Institute of Technology , Harbin 150001, P. R. China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Yu
authors.affiliation: School of Materials Science and Engineering, Harbin Institute of Technology , Harbin 150001, P. R. China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: School of Materials Science and Engineering, Harbin Institute of Technology , Harbin 150001, P. R. China.|State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology , Harbin 150001, P. R. China.
authors.forename: Wei-Dong
authors.initials: WD
authors.lastname: Fei
keywords: defect engineering; lattice distortion; lead-free; piezoelectric; temperature-stability