Electric field-induced phase transitions and composition-driven nanodomains in rhombohedral-tetragonal potassium-sodium niobate-based ceramics
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KAUST DepartmentPhysical Sciences and Engineering (PSE) Division
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AbstractThe mechanisms behind the high piezoelectricity of (K,Na)NbO3-based lead-free ceramics were investigated, including electric field-induced phase transitions and composition-driven nanodomains. The construction of a rhombohedral-tetragonal (R-T) phase boundary, confirmed using several advanced techniques, allowed a large piezoelectric constant (d33) of 450 ± 5 pC/N to be obtained in (1-x)K0.4Na0.6Nb0.945Sb0.055O3-xBi0.5Na0.5(Hf1-ySny)O3 (0 ≤ x ≤ 0.06 and 0 ≤ y ≤ 0.5) ceramics possessing an ultralow ΔUT-R of 7.4 meV. More importantly, the existence of an intermediate phase, i.e., the electric-induced phase (EIP), bridging the rhombohedral R [Ps//(111)] and tetragonal T [Ps//(001)] phases during the polarization rotation was demonstrated. Striped nanodomains (∼40 nm) that easily responded to external stimulation were also observed in the ceramics with an R-T phase. Thus, the enhanced piezoelectric properties originated from EIP and the striped nanodomains.
CitationLv X, Wu J, Xiao D, Zhu J, Zhang X (2017) Electric field-induced phase transitions and composition-driven nanodomains in rhombohedral-tetragonal potassium-sodium niobate-based ceramics. Acta Materialia. Available: http://dx.doi.org/10.1016/j.actamat.2017.08.009.
SponsorsThe authors gratefully acknowledge that the research reported in this publication was supported by the National Science Foundation of China (NSFC Nos., 51332003 and 51272164) and the King Abdullah University of Science and Technology (KAUST). The authors thank Mr. Yueliang Gu (Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Pudong New Area, Shanghai 201204, P. R. China) for measuring the in situ XRD patterns, Mr. Chenhui Zhang for calculating the energy of the O-T and R-T phase coexistence, and Mr. Qiang Zhang for measuring the TEM patterns.