Publication Date:
2011-03-15
Description:
(Na 0.85 K 0.15 ) 0.5 Bi 0.5 TiO 3 (NKBT) and B-site-substituted NKBT by Sc, i.e. (Na 0.85 K 0.15 ) 0.5 Bi 0.5 Ti (1− x ) Sc x O 3 (NKBT-Sc x , x =0.05, 0.1, 0.15, 0.2, 0.25, 0.3, and 0.4) thin films were prepared on Pt/Ti/SiO 2 /Si(100) substrates by an aqueous sol–gel method. Structures and electrical characteristics of the films were studied as functions of Sc composition. Structures were investigated by X-ray diffraction (XRD), scanning probe microscopy, scanning electron microscopy, and Raman spectroscopy. XRD indicates that a secondary phase peak appears when Sc-doping concentration increases above x =0.25 due to the limited substitution tolerance of Sc 3+ for Ti 4+ . With increasing Sc-doping composition, generally, the octahedra-related vibration modes show a high-frequency shift. The remnant polarization ( P r ) value is a maximum for the NKBT-Sc0.25 films of 18.62 μC/cm 2 and decreases with both decreasing and increasing doping concentration. The NKBT-Sc thin film with an optimized Sc-doping concentration of x =0.25 shows the effective piezoelectric coefficient d 33 * of 67 pm/V. The Curie temperature ( T c ) of the NKBT thin film shifted to higher temperature by adding Sc dopant.
Print ISSN:
0002-7820
Electronic ISSN:
1551-2916
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
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