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Titolo:
Magnetic properties of Ba4Co2Fe36O60 nanocrystals prepared through a sol-gel method
Autore:
Xiong, G; Xu, M; Mai, ZH;
Indirizzi:
Chinese Acad Sci, Inst Phys, Beijing 100080, Peoples R China Chinese Acad Sci Beijing Peoples R China 100080 100080, Peoples R China Chinese Acad Sci, Ctr Condensed Matter, Beijing 100080, Peoples R China Chinese Acad Sci Beijing Peoples R China 100080 100080, Peoples R China
Titolo Testata:
SOLID STATE COMMUNICATIONS
fascicolo: 1, volume: 118, anno: 2001,
pagine: 53 - 58
SICI:
0038-1098(2001)118:1<53:MPOBNP>2.0.ZU;2-N
Fonte:
ISI
Lingua:
ENG
Soggetto:
BARIUM FERRITE; HEXAGONAL FERRITES; PARTICLES; FINE; POWDERS; CRYSTALLIZATION; COPRECIPITATION; DYNAMICS; SIZE; CO;
Keywords:
nanostructures; surface and interface; chemical synthesis;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
--discip_EC--
Citazioni:
28
Recensione:
Indirizzi per estratti:
Indirizzo: Xiong, G Chinese Acad Sci, Inst Phys, POB 603, Beijing 100080, Peoples R China Chinese Acad Sci POB 603 Beijing Peoples R China 100080 R China
Citazione:
G. Xiong et al., "Magnetic properties of Ba4Co2Fe36O60 nanocrystals prepared through a sol-gel method", SOL ST COMM, 118(1), 2001, pp. 53-58

Abstract

Ba4CO2Fe36O60 (Co-2-U) nanocrystals were synthesized through a stearic acid sol-gel method. The reaction temperatures were dramatically lower than those prepared through the conventional ceramic method. The nanocrystalline powders obtained at 750 degreesC were approximately spherical in shape with grain sizes ranging from 10 to 25 nm and became cubic-like when the heat-treatment temperature was increased. The surface composition of the nanocrystalline Ba4Co2Fe36O60 was found to be different from that of the bulk counterpart material, exhibiting a higher content of Ba and Co. The magnetic properties of these samples are clearly size-dependent. The specific saturationmagnetization is lower than that of bulk Ba4Co2Fe36O60 and decreases with the grain size D. This phenomenon is explained by assuming the existence ofa nonmagnetic layer on the surface of the particles. The coercivity of Ba4Co2Fe36O60 nanocrystals reaches a maximum when the particle sizes are approximately equal to 80 nm and then decreases notably as the particle sizes are further reduced. These results are attributed to the superparamagnetic effects in a random distribution of single domain ferromagnetic particles. (C) 2001 Elsevier Science Ltd. All rights reserved.

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Documento generato il 05/12/20 alle ore 20:15:32