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Structural and magnetic properties of α‐Fe 2 O 3 nanoparticles
Author(s) -
Suber Lorenza,
Santiago Antoni García,
Fiorani Dino,
Imperatori Patrizia,
Testa Alberto Maria,
Angiolini Massimo,
Montone Amelia,
Dormann Jean L.
Publication year - 1998
Publication title -
applied organometallic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.53
H-Index - 71
eISSN - 1099-0739
pISSN - 0268-2605
DOI - 10.1002/(sici)1099-0739(199805)12:5<347::aid-aoc729>3.0.co;2-g
Subject(s) - acicular , morin , chemistry , nanoparticle , magnetization , particle size , trigonal crystal system , condensed matter physics , magnetic nanoparticles , particle (ecology) , magnetic field , nanotechnology , nuclear magnetic resonance , crystallography , crystal structure , materials science , microstructure , physics , medicine , oceanography , pathology , quantum mechanics , geology
The magnetic properties of α‐Fe 2 O 3 nanoparticles of different shapes (spherical, rhombohedral and acicular), prepared as powders by a chemical route, have been investigated. The particle size effect on the Morin transition ( T M = 263 K in the bulk system) have been studied by analyzing the temperature dependence of the zero‐field‐cooled (ZFC) and field‐cooled (FC) magnetization. For spherical (average diameter between 10 and 50 nm) and rhombohedral (edge between 30 and 350 nm) particles, the Morin temperature was found to decrease with decreasing particle size and increasing magnetic field. On the other hand, acicular particles (major axis between 300 and 700 nm, minor axis between 70 and 100 nm) do not show the Morin transition, unless annealed. © 1998 John Wiley & Sons, Ltd.