钙钛矿陶瓷La_(1-x)Ca_xMnO_3(x=0.10,0.15,0.20)的光电子能谱

X-Ray Photoelectron Spectroscopy for La_(1-x)Ca_xMnO_3(x=0.10,0.15,0.20)

对溶胶凝胶法制备的钙掺杂LaMnO3多晶陶瓷材料La1--xCaxMnO3(x=0.10,0.15,0.20)进行了X射线衍射和各个元素的光电子能谱研究,其X射线衍射实验表明:该系列样品表现出很好的单相性,其空间结构为正交型Pbnm。Mn 2p,La4d,O 1s能级的光电子能谱结果表明:当掺杂浓度较低时,Ca离子在La位的掺杂不会引起La和O元素电子组态的变化,只引起Mn离子的化学价态变化。利用组态相互作用团簇模型计算了Mn 2p光电子能谱,得到晶体场分裂能10 Dq=1.0eV,电荷转移能Δ=5eV,d轨道之间的库伦排斥能Udd=4eV,pd轨道之间的库伦排斥能Upd=4.4eV,过渡金属离子d轨道和近邻O离子之间的轨道杂化能T(eg)=3.8eV。

The Lal-x Cax MnO3 （x= 0. 10, 0. 15,0.20） was prepared by a sol-gel method. The samples were characterized by X- ray diffraction and X-ray photoelectron spectroscopy. According to the results by XRD, these samples are a well-single phase with the Pbnm orthorhombic crystal structure. From the XPS spectra of Mn 2p, La 4d, O ls core levels, there is little chemical shift for La and O ions, but a slight change for Mn ions at a low doping concentration. The Mn 2：0 core level was also calculat- ed by a configuration interaction cluster model. The parameters are crystal field splitting energy （10Dq） of 1.0 eV, charge transfer （A） of 5 eV, dd Coulombic repulsion potential （Udd） of 4 eV, pd Coulombic repulsion potential （U,pd） of 4.4 eV, and energy of transitional metal d orbital hybridized with ligand oxygen orbital （T（ eg ）） of 3.8 eV, respectively.