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Author Wang, Y. Q. ♦ Maclaren, Ian ♦ Duan, X. F. ♦ Wang, Z. H. ♦ Shen, B. G.
Sponsorship (US)
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Publisher The American Physical Society
Language English
Subject Keyword CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS ♦ CATIONS ♦ ELECTRONS ♦ ENERGY-LOSS SPECTROSCOPY ♦ MANGANESE ♦ MODULATION ♦ PHYSICS ♦ TRANSMISSION ELECTRON MICROSCOPY ♦ VALENCE
Abstract Electron energy-loss spectroscopy (EELS) has been used to determine the valence state of manganese for all the samples at low temperature (93 K). EELS results indicate that the valence state of manganese keeps constant ({similar_to}3.5) for all the samples. The effects of the A-site cation size mismatch on the charge ordering (CO) behaviors in the manganites (La{sub 1{minus}x}Y{sub x}){sub 0.5}(Ca{sub 1{minus}y}Sr{sub y}){sub 0.5}MnO{sub 3} are studied by transmission electron microscopy (TEM). TEM images show that the size mismatch and disorder of A-site cations have a suppression effect on the CO transition. The schematic models are proposed for the incommensurate CO modulation in the samples with size mismatch {sigma}{sup 2}{le}0.003. The disappearance of the CO transition in the sample with the largest mismatch ({sigma}{sup 2}=0.005) is explained by the random arrangements of Mn{sup 3+} and Mn{sup 4+} ions. {copyright} 2001 American Institute of Physics.
ISSN 00218979
Educational Use Research
Learning Resource Type Article
Publisher Date 2001-07-01
Publisher Place United States
Journal Journal of Applied Physics
Volume Number 90
Issue Number 1


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