State Key Laboratory of Solidification Processing, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi'an 710072, PR China.
Dalton Trans. 2012 Aug 28;41(36):11046-54. doi: 10.1039/c2dt31085f.
Aurivillius ferroelectrics K(0.25)Na(0.25)La(0.5)Bi(2)Nb(2)O(9) (KNBN-La) and K(0.25)Na(0.25)Bi(2.5)Nb(2)O(9) (KNBN-Bi) were prepared by using solid-state reaction process. Rietveld refinements for the KNBN-La and KNBN-Bi were carried out by using powder X-ray diffraction at room temperature and they were confirmed to be two-layer Aurivillius oxides with orthorhombic space group A2(1)am. The lattice parameters are a = 5.50468(10) Å, b = 5.49217(10) Å, and c = 25.05108(35) Å for KNBN-La and a = 5.48867(6) Å, b = 5.47895(6) Å, and c = 25.10591(25) Å for KNBN-Bi. Lanthanum (La(3+)) substitution for bismuth (Bi(3+)) led to an enhancement in relaxation behavior for the KNBN-La ceramics, with a ferroelectric to paraelectric phase transition temperature (T(c)) of about 360 °C. The KNBN-La ceramics had a high remnant polarization (P(r)) of 13.6 μC cm(-2) and a field-induced strain of up to 0.031%. Particularly, the decrease in P(r) for the KNBN-La ceramics after 10(8) cumulative switching cycles was only 6%.
钙钛矿型铁电体 K(0.25)Na(0.25)La(0.5)Bi(2)Nb(2)O(9) (KNBN-La) 和 K(0.25)Na(0.25)Bi(2.5)Nb(2)O(9) (KNBN-Bi) 是通过固相反应法制备的。在室温下通过粉末 X 射线衍射对 KNBN-La 和 KNBN-Bi 进行了 Rietveld 精修，它们被确认为具有正交空间群 A2(1)am 的两层 Aurivillius 氧化物。晶格参数为 KNBN-La 的 a = 5.50468(10) Å、b = 5.49217(10) Å 和 c = 25.05108(35) Å，KNBN-Bi 的 a = 5.48867(6) Å、b = 5.47895(6) Å 和 c = 25.10591(25) Å。镧(La(3+))取代铋(Bi(3+))导致 KNBN-La 陶瓷的弛豫行为增强，铁电-顺电相转变温度(T(c))约为 360°C。KNBN-La 陶瓷具有 13.6 μC cm(-2)的高剩余极化强度(P(r))和高达 0.031%的场致应变。特别是，KNBN-La 陶瓷在 10(8)次累积开关循环后 P(r)的下降仅为 6%。
