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	Magnetic properties of undoped Cu/sub 2/O fine powders with magnetic impurities and/or cation vacancies
	Chinping Chen ; Lin He ; Lin Lai ; Hua Zhang ; Jing Lu ; Lin Guo ; Yadong Li
	2010-10-12 ; 2010-10-12
关键词	Theoretical or Mathematical Experimental/ cobalt copper compounds density functional theory diamagnetism ferromagnetism ground states iron magnetic impurities magnetic moments magnetic particles magnetic susceptibility magnetisation nanostructured materials nanotechnology nickel paramagnetism particle size semiconductor doping semiconductor growth semimagnetic semiconductors vacancies (crystal)/ magnetic properties magnetic impurities cation vacancies fine powders micron sized particles undoped semiconductor particle morphology chemical processes magnetic susceptibility diamagnetism nanosphere paramagnetism polyhedron samples saturation magnetization impurity concentration density functional theory defect-induced magnetic moments ferromagnetically coupled ground state diluted magnetic semiconductor size 200 nm size 800 nm size 1 mum temperature 5 K Cu/sub 2/O:Fe Cu/sub 2/O:Co Cu/sub 2/O:Ni/ A8116 Methods of nanofabrication and processing A7530H Magnetic impurity interactions A6170W Impurity concentration, distribution, and gradients A7560J Fine-particle magnetic systems A7530C Magnetic moments and susceptibility in magnetically ordered materials A7520C Diamagnetism and paramagnetism in nonmetals A7560E Magnetization curves, hysteresis, Barkhausen and related effects A7115M Density functional theory, local density approximation (condensed matter electronic structure) A6170B Interstitials and vacancies A7550P Magnetic semiconductors A6146 Structure of solid clusters, nanoparticles, nanotubes and nanostructured materials B2550B Semiconductor doping B2520E Oxide and ferrite semiconductors/ size 2.0E-07 m size 8.0E-07 m size 1.0E-06 m temperature 5.0E+00 K/ Cu2O:Fe/ss Cu2O/ss Cu2/ss Cu/ss Fe/ss O/ss Cu2O/bin Cu2/bin Cu/bin O/bin Fe/el Fe/dop Cu2O:Co/ss Cu2O/ss Cu2/ss Co/ss Cu/ss O/ss Cu2O/bin Cu2/bin Cu/bin O/bin Co/el Co/dop Cu2O:Ni/ss Cu2O/ss Cu2/ss Cu/ss Ni/ss O/ss Cu2O/bin Cu2/bin Cu/bin O/bin Ni/el Ni/dop
中文摘要	Fine powders of micron- and submicron-sized particles of undoped Cu/sub 2/O semiconductor, with three different sizes and morphologies, have been synthesized by different chemical processes. These samples include nanospheres 200 nm in diameter, octahedra of size 1 mu m and polyhedra of size 800 nm. They exhibit a wide spectrum of magnetic properties. At low temperature, T = 5 K, the octahedron sample is diamagnetic with the magnetic susceptibility chi /sub OH/ = -9.5 * 10 /sup -6/ emu g /sup -1/ Oe /sup -1/ . The nanosphere is paramagnetic with chi /sub NS/ = 2.2 * 10 /sup -5/ emu g /sup -1/ Oe /sup -1/ . The other two polyhedron samples synthesized in different runs by the same process are found to show different magnetic properties. One of them exhibits weak ferromagnetism with T /sub C/ ~455 K and saturation magnetization M /sub S/ ~0.19 emu g /sup -1/ at T = 5 K, while the other is paramagnetic with chi = 1.0 * 10 /sup -5/ emu g /sup -1/ Oe /sup -1/ . The total magnetic moment estimated from the detected impurity concentration of Fe, Co and Ni, is too small to account for the observed magnetism by one to two orders of magnitude. Calculations by density functional theory (DFT) reveal that cation vacancies in the Cu/sub 2/O lattice are one of the possible causes of induced magnetic moments. The results further predict that the defect-induced magnetic moments favour a ferromagnetically coupled ground state if the local concentration of cation vacancies, n /sub C/ , exceeds 12.5%. This offers a possible scenario to explain the observed magnetic properties. The limitations of the investigations in the present work, in particular in the theoretical calculations, are discussed and possible areas for further study are suggested.
语种	英语
出版者	IOP Publishing Ltd. ; UK
内容类型	期刊论文
源URL	[http://hdl.handle.net/123456789/81076]
专题	清华大学
推荐引用方式 GB/T 7714	Chinping Chen,Lin He,Lin Lai,et al. Magnetic properties of undoped Cu/sub 2/O fine powders with magnetic impurities and/or cation vacancies[J],2010, 2010.
APA	Chinping Chen.,Lin He.,Lin Lai.,Hua Zhang.,Jing Lu.,...&Yadong Li.(2010).Magnetic properties of undoped Cu/sub 2/O fine powders with magnetic impurities and/or cation vacancies..
MLA	Chinping Chen,et al."Magnetic properties of undoped Cu/sub 2/O fine powders with magnetic impurities and/or cation vacancies".(2010).

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