Competition between Band Filling and Steric Effect in Ordered Double Perovskites Sr_(2-x)La_xMnMoO_6  

作　　者：田世哲 赵军钗 乔从德 姬相玲 姜炳政 

机构地区：[1]State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022,China

出　　处：《Journal of Rare Earths》2006年第6期679-684,共6页稀土学报（英文版）

基　　金：Project supported bythe National Natural Science Foundation of China (50073024 ,90101001) ;the Special Funds for MajorState Basic Research Projects (G1999064800) ;the Project fromthe Chinese Academy of Sciences (KJCX2-SW-H07) ;the In-ternational Collaboration Project from Changchun City ,China (04-03GH268)

摘　　要：The ordered double perovskites, Sr2-xLaxMnMoO6, were prepared by sol-gel reaction. Structural, magnetic, and electrical properties were investigated for a series of ordered double perovskites Sr2- x Lax MnMoO6 （0 ≤ x ≤ 1 ）. The compounds have a monoclinic structure （space group P21/n） and the cell volume expands monotonically with La doping. The Tc and the magnetic moment rise and the cusp-like transition temperature below which the magnetic frustration occurs shifts to high temperature as x increases. With La doping, electrical resistivity of Sr2-x LaxMnMoO6 decreases only at low doping levels （x ≤0.2）; while at high doping levels （0.8≤x ≤1）, electrical resistivity tends to increase greatly. The resuits suggest that the competition between band filling effect and steric effect coexists in the whole doping range, and the formation of ferrimagnetic interactions is not simply at the expense of antiferromagnetic interactions.The ordered double perovskites, Sr2-xLaxMnMoO6, were prepared by sol-gel reaction. Structural, magnetic, and electrical properties were investigated for a series of ordered double perovskites Sr2- x Lax MnMoO6 （0 ≤ x ≤ 1 ）. The compounds have a monoclinic structure （space group P21/n） and the cell volume expands monotonically with La doping. The Tc and the magnetic moment rise and the cusp-like transition temperature below which the magnetic frustration occurs shifts to high temperature as x increases. With La doping, electrical resistivity of Sr2-x LaxMnMoO6 decreases only at low doping levels （x ≤0.2）; while at high doping levels （0.8≤x ≤1）, electrical resistivity tends to increase greatly. The resuits suggest that the competition between band filling effect and steric effect coexists in the whole doping range, and the formation of ferrimagnetic interactions is not simply at the expense of antiferromagnetic interactions.

关 键 词：double perovskite band filling steric effect FERRIMAGNETISM rare earths 

分 类 号：O482.54[一般工业技术—材料科学与工程] TM277[理学—固体物理]