Topochemical transformation of two-dimensional single crystalline Na<inf>0.5</inf>Bi<inf>0.5</inf>TiO<inf>3</inf>-BaTiO<inf>3</inf> platelets from Na<inf>0.5</inf>Bi<inf>4.5</inf>Ti<inf>4</inf>O<inf>15</inf> precursors and their piezoelectricity
15780 - 15788
Journal of Materials Chemistry A
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Two-dimensional monocrystalline platelets of the perovskite structured lead-free system (Na 0.5 Bi 0.5 ) 0.93 Ba 0.07 TiO 3 (NBBT) were synthesized from platelets of layer-structured Na 0.5 Bi 4.5 Ti 4 O 15 (NBIT), using a topochemical route. Both NBIT and NBBT platelets showed high aspect ratios with an average size of 10 μm and thickness of 0.6 μm, for the latter. A structural transformation from layer-structured NBIT to perovskite NBBT was identified in a transitional platelet, which contained phases of both NBIT and NBBT. The composition of NBBT lies at a morphotropic phase boundary (MPB), with the coexistence of monoclinic and tetragonal polymorphs confirmed by X-ray powder diffraction analysis. Transmission electron microscopy and piezoresponse force microscopy were used to investigate the domain structure, with stripe-like domains in the unpoled system transformed into lamellar domains after poling. The piezoresponse amplitude for a NBBT platelet indicated a large piezoresponse strain, corresponding to a field-induced strain S max /E max of around 800 pm V -1 at 5 kV mm -1 , which is significantly higher than that in ceramic samples of NBBT at the same applied potential.
AuthorsJiang, C; Zhang, D; Zhou, K; Yan, H; Zhang, H; Abrahams, I
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