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Title: Structure, dielectric, and piezoelectric properties of CuO-doped K[sub 0.5]Na[sub 0.5]NbO₃-BaTiO₃ lead-free ceramics
Authors: Lin, Dunmin
Kwok, Kin-wing
Chan, Helen L. W.
Subjects: Barium compounds
Copper compounds
Crystal structure
Densification
Dielectric losses
Dielectric polarisation
Dielectric relaxation
Ferroelectric Curie temperature
Piezoceramics
Potassium compounds
Sodium compounds
Issue Date: 11-Oct-2007
Publisher: American Institute of Physics
Citation: Journal of applied physics, 11 Oct. 2007, v. 102, 074113, p. 1-6
Abstract: Lead-free piezoelectric ceramics (1−x)K[sub 0.5]Na[sub 0.5]NbO₃+xBaTiO₃+y mol % CuO have been fabricated by an ordinary sintering technique. Our results show that the doping of CuO is effective in promoting the densification of the ceramics. With the doping of CuO, all the ceramics can be well sintered and exhibit a dense, pure perovskite structure. After the formation of a solid solution with BaTiO₃, both the paraelectric cubic-ferroelectric tetragonal and ferroelectric tetragonal-ferroelectric orthorhombic phase transition temperatures decrease and a relax behavior is induced. Coexistence of the orthorhombic and tetragonal phases is formed in the ceramics with 0.04≤x≤0.06 and y=1.00 at room temperature. Because of the more possible polarization states arising from the coexistence of the two phases and the improved densification, the piezoelectric and dielectric properties of the ceramics are enhanced significantly. The ceramic with x=0.06 and y=1.00 exhibits the optimum properties: d[sub 33]=193 pC/N, k[sub p]=0.43, k[sub t]=0.40, and T[sub C]=314 °C. On the other hand, the ceramics with 0≤x≤0.01 and y=1.0 exhibit excellent “hard” piezoelectric characteristics: k[sub p]~0.40, k[sub t]~0.47, Q[sub m]~1940, ε[sub r]~230, and tan δ~0.5%.
Rights: © 2007 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in D. Lin, K.W. Kwok, & H.L.W. Chan. J. Appl. Phys. 102, 074113 (2007) and may be found at http://link.aip.org/link/?jap/102/074113
Type: Journal/Magazine Article
URI: http://hdl.handle.net/10397/394
ISSN: 00218979
Appears in Collections:MRC Journal/Magazine Articles
AP Journal/Magazine Articles

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