Doping effects with respect to the electrical properties of morphotropic phase boundary ͑Bi 0.5 Na 0.5 ͒ 0.94 Ba 0.06 TiO 3 thin films epitaxially grown on CaRuO 3 electroded ͑LaAlO 3 ͒ 0.3 ͑Sr 2 AlTaO 6 ͒ 0.35 ͑001͒ substrates were investigated. Substantial enhancement of ferroelectricity and piezoelectricity has been achieved in La+ Ce codoped films with a remanent polarization P r of 29.5 C / cm 2 and a remanent piezoelectric coefficient d 33,f of 31 pm/V, whereas Mn doping seems more favorite to reduce the leakage current by two order of magnitude. Both doped films exhibited diodelike I-V characteristics, which are correlated with resistance switching effect. © 2010 American Institute of Physics. ͓doi:10.1063/1.3518484͔Due to the increasing environmental and biological concerns on high toxicity of lead present in the widely used Pb͑Zr, Ti͒O 3 ͑PZT͒ family, considerable attention has been drawn to develop lead-free ferroelectric materials in the past two decades. 1 Among various potential lead-free piezoelectric ceramics, A-site complex perovskite ͑Bi 0.5 Na 0.5 ͒TiO 3 ͑BNT͒ is considered to be one of the strong candidates because of its marked ferroelectricity/piezoelectricity. 2,3 The pioneer work by Takenaka et al. 4 demonstrated that rhombohedral ͑F ␣ ͒-tetragonal ͑F ␤ ͒ morphotropic phase boundary ͑MPB͒ in ͑Bi 0.5 Na 0.5 ͒TiO 3 -BaTiO 3 ͑BNBT͒ binary system is remarkably effective in promoting piezoelectric properties. Subsequent studies revealed the piezoelectric performance of BNBT ceramics with MPB composition could be further enhanced by appropriate dopants. [5][6][7] In spite of the numerous studies on BNT-based single crystals and ceramics, literature tackling with the growth and characterization of BNT-based, especially BNBT-based thin films, still remains at an infancy stage. [8][9][10][11][12] Consequently, doping effects on the electrical properties of thin film BNBT materials are still unclear. Abazari et al. 13 has recently reported epitaxial potassium modified BNBT thin films grown on SrRuO 3 coated SrTiO 3 substrates by pulsed laser deposition ͑PLD͒. Dielectric and piezoelectric properties of the films were evaluated macroscopically. However, the nanoscale characterization of piezoresponse of doped BNBT thin films is still missing. In this letter, thin films of La+ Ce codoped and Mn-doped BNBT with composition in the vicinity of MPB are epitaxially deposited on CaRuO 3 ͑CRO͒ electroded ͑LaAlO 3 ͒ 0.3 ͑Sr 2 AlTaO 6 ͒ 0.35 ͑LSAT͒ ͑001͒ singlecrystal substrates by PLD. Effects of dopants on ferroelectric, dielectric, leakage current, and local piezoelectric properties of the BNBT-based thin films are investigated.The 10% Bi-enriched targets of ͑Bi 0.5 Na 0.5 ͒ 0.94 Ba 0.06 TiO 3 + 0.5 mol % CeO 2 + 0.5 mol % La 2 O 3 ͑BNBT-LaCe͒, ͑Bi 0.5 Na 0.5 ͒ 0.94 Ba 0.06 TiO 3 + 0.5 mol % MnO 2 ͑BN-BTMn͒ used for laser ablation were fabricated by the conventional solid state reaction route. The substrates were cubic ͑001͒-oriented LSAT ͑a = 3.868 Å͒, which were first coated a layer of CRO ͑ϳ40 nm͒ by PLD...

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Large plate-like Na 0.5 Bi 0.5 TiO 3 (NBT) templates have been successfully synthesized from bismuth layer-structured ferroelectric Na 0.5 Bi 4.5 Ti 4 O 15 (NBIT) particles by the topochemical method. Because of the highly anisotropic structure, plate-like NBIT particles were first synthesized by the molten-salt process. After the topochemical reaction with the complementary reactants (Na 2 CO 3 , and TiO 2 ) in NaCl flux, the layer-structured NBIT particles were transformed to the perovskite NBT templates. The resulting NBT templates are large and of plate-like shape. Our results also reveal that they are more effective in inducing grain orientation in the BNKT-BT ceramics as compared with BIT templates. For a BNKT-BT ceramic textured with 20 wt% of NBT templates, it exhibits a very high degree of grain orientation and gives a large Lotgering factor of 0.89. J ournal

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