Facile synthesis of inverse spinel NiFe2O4 nanocrystals and their superparamagnetic properties

Spinel NiFe2O4 nanocrystals have been obtained by means of a novel composite-hydroxide-salt-mediated approach, which is based on a reaction between metallic salt and metallic oxide in the solution of composite-hydroxide-salt eutectic at ~225 ºC and normal atmosphere without any organic dispersant or...

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Bibliographic Details
Published in:Materials research (São Carlos, São Paulo, Brazil) São Paulo, Brazil), 2012-01 (ahead), p.0
Main Authors: Jie Tan, Wei Zhang, Ai-Lin Xia
Format: Article
Language:English
Subjects:
magnetic properties
mechanism
morphology
NiFe2O4 nanocrystals
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Summary:Spinel NiFe2O4 nanocrystals have been obtained by means of a novel composite-hydroxide-salt-mediated approach, which is based on a reaction between metallic salt and metallic oxide in the solution of composite-hydroxide-salt eutectic at ~225 ºC and normal atmosphere without any organic dispersant or capping agent. The obtained products are characterized by an X-ray diffraction (XRD), a transmission electron microscopy (TEM) and an alternating gradient magnetometer (AGM). The formation process of NiFe2O4 nanosheet is proposed to begin with a ‘‘dissolution-recrystallization’’ which is followed by an ‘‘Ostwald ripening’’ mechanism. The NiFe2O4 nano-octahedrons can be obtained through adjusting the reaction water content in the hydroxide melts at constant temperature. At 300 K, magnetic hysteresis loops at an applied field of 15 kOe show zero coercivity, indicating the superparamagnetic behavior of the as-prepared NiFe2O4 nanocrystals.
ISSN:1516-1439
DOI:10.1590/S1516-14392012005000157