硅酸盐学报

La^3＋掺杂对焦绿石型Bi₂O₃-ZnO-Nb₂O₅陶瓷结构和介电性能的影响

作者：张倩丁士华宋天秀曾卓玮钟祥清

关键词：立方焦绿石结晶化学介电弛豫

分类号：TM22

出版年,卷(期):页码：2014,42(6):729-733

DOI：10.7521/j.issn.0454-5648.2014.06.08

摘要：

采用固相反应法制备(Bi1.5LaxZn0.5-x)(Zn0.5＋xNb1.5-x)O7(BZNL，x＝0.01～0.07mol)焦绿石型陶瓷。利用X射线衍射仪和高阻抗分析仪(LCR)对样品结构、结晶化学特性与介电性能进行表征。结果表明：所有陶瓷样品均保持单一的立方焦绿石相；随La3＋替代量的增加，陶瓷样品中A位阳离子与8b位O′的平均键长r(O′—A)从0.22836nm增加到0.22846nm；键价和AV(O′) [Bi3La]、AV(O′) [Bi2ZnLa]、AV(O′) [Bi2La2]、AV(O′) [BiZn2La]随之减小；48f位氧的坐标ζ从0.02827nm增加到0.02903nm；样品的介电弛豫峰值温度Tm向低温方向移动，峰值介电常数εm依次减小，当替代量x＝0.07mol时，介电弛豫峰值温度Tm降低到最低温度(-107.4℃)，峰值介电常数εm为136.35。样品介电弥散性的增强与八面体结构的转变有关。

(Bi1.5LaxZn0.5-x)(Zn0.5＋xNb1.5-x)O7 (BZNL，x＝0.01-0.07mol) ceramic was prepared via solid phase reaction. The effect of La3＋on the structure, crystal chemistry and dielectric properties was investigated by X-ray diffraction and a high-precision LCR meter. The results reveal that all the samples exhibit a single cubic pyrochlore phase. The average distance R(O′—A) of BZNL ceramics increases from 0.228 36 to 0.228 46 nm, the bond valence sums AV(O′) [Bi3La]，AV(O′) [Bi2ZnLa]，AV(O′) [Bi2La2]，AV(O′) [BiZn2La] all decrease, the ζ coordinate of the 48f oxygen increases from 0.028 27 to 0.029 03 nm, the temperature of maximum dielectric constant Tm shifts towards lower temperature and the maximum value of dielectric constant εm decreases when La3＋content increases. When x＝0.07 mol, the temperature of maximum dielectric constant Tm decreases to the lowest temperature (-107.4℃), and the maximum dielectric constant εm is 136.35. The increase of relaxation behavior could be closely related to the change of octahedral.

基金项目：

国家自然科学基金(11074203)；教育部春晖计划 (Z2011077)；西华大学研究生创新基金(YCJJ201303，YCJJ201306)资助项目。

作者简介：

第一作者：张　倩(1988—)，女，硕士研究生。通信作者：丁士华(1963—)，男，博士，教授。

参考文献：

[1]　YAN M F, LING H C, RHODES W W. Low-firing, temperature stable dielectric compositions based on bismuth nickel zinc niobates [J].J Am Ceram Soc, 1990, 73(4): 1106-1109.
[2]　CANN D P, RANDALL C A ,SHROUT T R. Investigation of dielectric properties of bismuth pyrochlores ［J］. Solid State Commun, 1996, 100(7): 529-534.
[3]　DING Shihua, YAO Xi, YUAN Li. Study of structure and dielectrc properties of nonstoichiometric Bi2O3-ZnO-Nb2O5 ceramics ［J］. J Electroceram, 2008, 21(1):435-438.
[4]　NINO J C， LANAGAN M T, RANDALL C A. Dielectric relaxation in Bi2O3-ZnO-Nb2O5 cubic pyrochlore ［J］. Jpn J Appl Phys, 2001, 89(8): 4512-4516.
[5]　WANG Qian, WANG Hong, YAO Xi. Structure, dielectric and optical properties of Bi1.5＋xZnNb1.5O7＋1.5x pyrochlores ［J］. Ceram Int, 2009, 35(1): 143-146.
[6]　WANG Hong, PENG Zhen, DU Huiling, et al. Mn4＋andW6＋ substitution on Bi1.5ZnNb1.5O7 based low firing ceramics ［J］. Ceram Int, 2004, 30(7): 1219-1223.
[7]　WANG Hang, STANISLA Kamba. Microwave and infrared dielectric response of monoclinic bismuth zinc niobate based pyrochloro ceramies with ion substitution in A site ［J］. Jpn J Appl Phys, 2006, 100(3): 034109-03410915.
[8]　王红妮，丁士华，宋天秀，等.Bi1.5-xCaxZnNb1.5O7陶瓷结构、介电性能与结晶化学特性[J].无机材料学报，2012, 27(11)：1164-1168.
WANG Hongni, DING Shihua, SONG Tianxiu, et al. J Inorg Mater (inChinese), 2012, 27(11): 1164-1168.
[9]　汪宏，张德生，姚熹.La3＋取代Bi3＋的Bi2O3-ZnO-Nb2O5基陶瓷的结构与介电性能 [J].硅酸盐学报，1998, 26(4): 532-536.
WANG Hong, ZHANG Desheng, Yao Xi. J Chin Ceram Soc, 1998, 26(4): 532-536.
[10]　徐琴，丁士华，等.Er3＋掺杂对立方焦绿石陶瓷结构与介电性能的影响[J].硅酸盐学报，2013, 41(12): 1609-1615.
XU Qin, DING Shihua, et al. J Chin Ceram Soc, 2013, 41(12): 1609-1615.
[11]　SHEN B, ZHAI J W, AND YAO X. Dielectric relaxation and tenability of Bi2O3-ZnO-CaO-Ta2O5 ceramics ［J］. Phys Rev Lett, 2005, 86(7): 072902-072903.
[12]　BRESE N E, O′KEEFFE M. Bond-valence parameters for solid ［J］. Acta Crystallogr Sect B, 1991, 47(2): 192-197.
[13]　WITHERS R L, WELBERRY T R, LARSSON A K, et al. Local crystal chem. istry induced strain and short range order in the cubicpyrochlore (Bil.5-αZn0.5-δ)(Zn0.5-γNb1.5-δ)O(7-1.5α-β-γ-2.5δ)［J］. J Solid State Chem, 2004, 177(1): 231-244.
[14]　L YUN, WITHERS R L, WELBERRy T R, et al. Crystal chemistry on a lattice: The case of BZN and BZN-related pyrochlores［J］. J Solid State Chem, 2006, 179(7):2141-2149.
[15]　SOMPHON W, TING V, LIU YUN, et al. Local crystal chemistry structured diffuse scattering and the dielectric properties of (Bi1-xYx)2(MIIINbV)O7 (M＝Fe3＋，In3＋) Bipyrochlores ［J］. J Solid State Chem, 2006, 179(8): 2495-2505.
[16]　SUBRAMANIAN M A, ARAVAMUDAN G, SUBBA-Rao G V. Oxide pyrochlores-A review ［J］. Prog Solid State Chem, 1983, 15: 55-143.
[17]　ZHI Y, CHEN A, RU G, et al. Ferroelectric relaxor behavior of Ba(Ti0.7Zr0.3)O3 ceramics ［J］. Jpn J Appl Phys, 2002, 92(5): 2655-2657.
[18]　CHEN A, ZHI Y, YOUN H J.et al. Low-temperature dielectric relaxation in the phyrochlore (Bi3/4Zn1/4)2(Zn1/4•Ta3/4)2O7 compound [J]. Phys Rev Lett, 2002, 80(25): 4807-4809.
[19]　LEVIN I，AMOS T．G，NINO J．C，et al．Structural study of an unusual cubic pyrochlore Bil.5Zn0.92Nb1.5O6.92［J］. J Solid State Chem, 2002, 168(1): 69-72.
[20]　LIU Yun, WITHERS R L,NGUYEN H B, et al.Displacive disorder and dielectric relaxation in the stoichiometric bismuth-containing pyrochlores, Bi2MIIINbO7 (M=In and Sc) ［J］. J Solid State Chem, 2009, 182(10), 2748-2755.

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