Effect of lanthanum and tungsten co-substitution on the structure and properties of new Aurivillius oxides Na sub(0.5)La sub(0.5)Bi sub(2)Nb sub(2-x)W sub(x)O sub(9)

New Aurivillius ferroelectrics Na sub(0.5)La sub(0.5)Bi sub(2)Nb sub(2-x)W sub(x)O sub(9) (NLBN-W, x= 0, 0.01, 0.02, 0.03, and 0.05) by lanthanum (La super(3+)) and tungsten (W super(6+)) co-substitution were prepared by using a solid-state reaction process. The crystal structure of Na sub(0.5)La su...

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Bibliographic Details
Published in:CrystEngComm 2012-10, Vol.14 (21), p.7201-7208
Main Authors: Long, Changbai, Fan, Huiqing, Li, Mengmeng, Li, Qiang
Format: Article
Language:English
Subjects:
Ceramics
Crystal structure
Diffraction
Ferroelectric materials
Lanthanum
Oxides
Piezoelectricity
Tungsten
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Summary:New Aurivillius ferroelectrics Na sub(0.5)La sub(0.5)Bi sub(2)Nb sub(2-x)W sub(x)O sub(9) (NLBN-W, x= 0, 0.01, 0.02, 0.03, and 0.05) by lanthanum (La super(3+)) and tungsten (W super(6+)) co-substitution were prepared by using a solid-state reaction process. The crystal structure of Na sub(0.5)La sub(0.5)Bi sub(2)Nb sub(1.98)W sub(0.02)O sub(9) (NLBN-W-0.02) was refined by the Rietveld method with powder X-ray diffraction at room temperature and it was confirmed to be a two-layer Aurivillius oxide with an orthorhombic space group A2 sub(1)am(a= 5.48754(8) Aa, b= 5.47967(9) Aa and c= 24.8523(4) Aa). The ferroelectric to paraelectric phase transition temperature (T sub(c)) of NLBN-W-0.02 is around 501 degree C, with prominent relaxation behavior. The NLBN-W-0.02 ceramics have a high piezoelectric coefficient (d sub(33) = 31 pC N super(-1)) and large remnant polarization (P sub(r) = 15.1 mu C cm super(-2)). The decrease in P sub(r) for the NLBN-W-0.02 ceramics after 10 super(7) switching cycles at 40 and 120 degree C is only 2 and 9%, respectively.
ISSN:1466-8033
DOI:10.1039/c2ce25718a