Nd^(3+)、Sm^(3+)和Eu^(3+)单掺杂NiTiO_(3)的光电磁性能

Optical,electrical,and magnetic properties of Nd^(3+),Sm^(3+),and Eu^(3+) single-doped NiTiO_(3)

采用溶胶−凝胶法合成纳米Ni_(1−x)R_(x)TiO_(3)(R=Nd、Sm和Eu,x=0、0.05和0.1)粉末,结合X射线衍射、扫描电子显微镜、X射线光电子能谱、拉曼光谱及综合物性测量系统等表征技术,系统研究了Nd、Sm和Eu掺杂对钛酸镍(NiTiO_(3))微观结构和光电磁性能的影响。结果表明:所有样品均出现O—Ti键和O—Ni键的电荷转移(200~365 nm),Ni^(2+)的^(3)A_(2g)(^(3)F)→^(3)T_(1g)(^(3)P)自旋容许跃迁(450 nm),^(1)T_(2g)(^(1)D)、^(1)A_(1g)(^(1)G)的自旋禁阻跃迁(490~520 nm)以及^(1)E_(g)(^(1)D)的自旋禁阻跃迁(743 nm)。Nd掺杂样品的吸收光谱在588 nm附近出现与八面体位置Nd^(3+)电子跃迁有关的吸收峰,样品从黄色变为绿色。所有样品均在室温下表现出反铁磁性和铁电性,且Ni位掺杂Nd、Sm和Eu能显著增强NiTiO_(3)的铁电性。掺杂离子半径较大的元素导致晶格畸变,促进铁电畴的转动,增强铁电性。

Nanosized Ni_(1−x)R_(x)TiO_(3)(R=Nd,Sm and Eu;x=0,0.05 and 0.1)powders were synthesized by sol-gel method.The effects of Nd,Sm,and Eu doping on the microstructure and optical,electrical,and magnetic properties of NiTiO_(3) were systematically studied using characterization techniques such as X-ray diffraction,scanning electron microscopy,X-ray photoelectron spectroscopy,Raman spectroscopy,and physical property measurement system.The results show that all samples exhibit charge transfer of O—Ti bonds and O—Ni bonds(200−365 nm),spin-allowed transition of Ni^(2+)from ^(3)A_(2g)(^(3)F)to ^(3)T_(1g)(^(3)P)(450 nm),spin-forbidden transitions of ^(1)T_(2g)(^(1)D)and ^(1)A_(1g)(^(1)G)(490−520 nm),and spin-forbidden transition of 1Eg(1D)(743 nm).Absorption spectra of Nddoped samples exhibit an absorption peak near 588 nm correlated with the electronic transition of Nb^(3+) at the octahedral position,which change the samples color from yellow to green.All samples exhibit antiferromagnetism and ferroelectricity at room temperature,and Nd,Sm,and Eu doping at the Ni site significantly enhance the ferroelectricity of NiTiO_(3).Doping elements with larger ionic radii cause lattice distortion,promote the rotation of ferroelectric domains,and enhancc the ferroelectricity.