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Ni and Ni–nickel oxide nanoparticles with different shapes and a core–shell structure

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Title Ni and Ni–nickel oxide nanoparticles with different shapes and a core–shell structure
 
Creator NAYAK, BIBHUTI B
VITTA, SATISH
NIGAM, AK
BAHADUR, DHIRENDRA
 
Subject magnetization
electric conductivity
nickel compounds
particle size analysis
crystal structure
 
Description Ni nanoparticles with different shapes and having a core–shell structure of Ni–nickel oxide have been prepared by a combination of chemical and gaseous reduction. The first step involves chemical reduction of nickel chloride in an aqueous medium with sodium borohydride (NaBH4). In the second step, the as prepared Ni-complex is reduced further in the presence of 2% H2 and 98% Ar gas mixture at different temperatures ranging from 550 °C to 850 °C. For gaseous reduction temperatures up to 750 °C, structural studies done at room temperature indicate a core–shell structure of Ni–Ni-oxide whereas for reduction at 850 °C, essentially a single phase of Ni is seen. The particle size ranges from 20 to 120 nm with different shapes for the particles: spherical, ellipsoidal, cylindrical, hexagonal, and polyhedral. The electrical resistivity in all the cases exhibits a typical metallic behavior and the absolute resistivity decreases with increasing gaseous reduction temperature, indicating a progressive reduction of Ni-oxide. The magnetization studied as a function of temperature and field shows a clear core–shell behavior: very high magnetization saturation fields and thermal hysteresis of magnetization
 
Publisher Elsevier
 
Date 2009-06-13T05:19:42Z
2011-12-08T07:59:41Z
2011-12-26T13:02:33Z
2011-12-27T05:49:00Z
2009-06-13T05:19:42Z
2011-12-08T07:59:41Z
2011-12-26T13:02:33Z
2011-12-27T05:49:00Z
2006
 
Type Article
 
Identifier Thin Solid Films 505(1-2), 109-112
0040-6090
10.1016/j.tsf.2005.10.018
http://hdl.handle.net/10054/1482
http://dspace.library.iitb.ac.in/xmlui/handle/10054/1482
 
Language en