Sm_(2)O_(3)掺杂PMN-PZT陶瓷的电学性能及机理分析

Electrical Properties and Mechanism Analysis of Sm_(2)O_(3) Doped PMN-PZT Ceramics

采用固相法制备0.21 Pb(Mg 1/3 Nb 2/3)O 3-0.79Pb(Zr 0.48 Ti 0.52)O 3+x%Sm 2O 3压电陶瓷,其中x=0、0.1、0.2、0.3、0.4、0.5.通过X射线衍射仪(XRD)、扫描电子显微镜(SEM)、X射线能谱仪(EDS)、激光拉曼光谱仪、测试陶瓷的压电常数(d 33)、相对介电常数(εr)及介质损耗(tanδ),研究Sm 2O 3掺杂对PMN-PZT陶瓷的物相组成、微观形貌、介电压电性能的影响,结合EDS和拉曼光谱对影响机理进行分析.结果表明,掺杂Sm 2O 3能调控PMN-PZT陶瓷的晶型,细化晶粒,适当降低烧结温度,还可以构筑极性纳米微区(PNRs)和无序局域结构,促使介电、压电性能提升.其机理主要是Sm 3+取代Pb 2+而产生铅空位,形成内部钉扎效应,晶粒细化导致畴壁密度增加,使得压电效应增强;极性纳米微区(PNRs)和无序局域结构的产生,改善材料的弛豫特性,提高介电性能.此外,可以结合EDS能谱和拉曼光谱表征极性纳米微区及局域结构,为介电、压电材料的设计和表征提供一种新的参考.

0.21Pb(Mg_(1/3)Nb_(2/3))O_(3)-0.79Pb(Zr_(0.48)Ti_(0.52))O_(3)+x%Sm_(2)O_(3)(x=0,0.1,0.2,0.3,0.4,0.5)piezoelectric ceramics were prepared by a conventional solid-state method.The phase composition and microstructure of ceramics were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),X-ray energy dispersive spectrometer(EDS),and laser Raman spectrometer.The piezoelectric constant(d _(33)),dielectric constant(ε_(r))and dielectric loss(tanδ)of ceramics were measured.The effects of Sm_(2)O_(3) doping on the phase composition,microstructure and dielectric properties of PMN-PZT ceramics were investigated,and the mechanism was analyzed by EDS and Raman spectroscopy.The results show that the crystal form of PMN-PZT ceramics can be controlled,the grains can be refined,and the sintering temperature can be appropriately reduced by doped Sm_(2)O_(3),in addition that,polar nano-domains(PNRs)and disordered local structures can be constructed to improve the dielectric and piezoelectric properties.The mechanism is mainly that Sm^(3+) replaces the position of Pb^(2+) to generate lead vacancies and form an internal pinning effect,and grain refinement leads to an increase in the density of domain wall,which enhances the piezoelectric effect;the generation of polar nano-regions(PNRs)and disordered local structures improve the relaxation properties of the material,which improves the dielectric properties.Furthermore,polar nano-domains and local structures can be characterized by combining EDS spectroscopy and Raman spectroscopy,which provide a new reference for the design and characterization of dielectric and piezoelectric materials.