Data di Pubblicazione:
2010
Abstract:
Rhombohedral shaped, single crystal hematite particles with narrow size distribution ( = 93 ± 2 nm) were prepared by hydrolysis of iron chloride and polymerisation in water. The results of field dependent magnetization measurements at different warmingcooling rates and ac susceptibility measurements at varying frequencies are reported and discussed. Thermal hysteresis (DeltaTM) associated with the Morin transition and field dependence of the Morin temperature (DeltaTM) are observed in warmingcooling cycles (DeltaTM = 25 and 13 K for H = 0.1 and 3 T, respectively) due to the first order phase transition. A frequency dependence of ac susceptibility is observed above TM, as a result of the relaxation of the magnetic moment of hematite particles in the weak-ferromagnetic phase.
Tipologia CRIS:
01.01 Articolo in rivista
Keywords:
MAGNETIC-PROPERTIES; ALPHA-FE2O3 NANOPARTICLES; SIZE; EXCHANGE
Elenco autori:
VASQUEZ MANSILLA, Marcelo; Peddis, Davide; Mari, Alessandra; Marchegiani, Giada; Fiorani, Dino; Imperatori, Patrizia; Suber, Lorenza
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