Magnetic properties of (Fe)(1-x)-(Al(2)O(3))(x) and (Fe(50)Ni(50))(1-x)-(Al(2)O(3))(x) nanocomposite magnetic media synthesized using gel like Al(2)O(3) matrix
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Title |
Magnetic properties of (Fe)(1-x)-(Al(2)O(3))(x) and (Fe(50)Ni(50))(1-x)-(Al(2)O(3))(x) nanocomposite magnetic media synthesized using gel like Al(2)O(3) matrix
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Creator |
VITTA, S
SINHA, V BAHADUR, D |
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Subject |
ni
particles diagnostics alloys metals intermetallics precipitation magnetic behavior |
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Description |
Composites with ferromagnetic nanoparticles, Fe and Fe(50)Ni(50), dispersed in Al(2)O(3) have been synthesized by a solution phase technique. The structure and magnetic properties of these composites with varying fractions of Al(2)O(3) have been investigated. Both Fe and Fe(50)Ni(50) nanoparticles are amorphous in the as-prepared state and become crystalline on heat treating with near equilibrium lattice parameters of 0.287 nm and 0.358 nm respectively. The interparticle distance increases with increasing Al(2)O(3) from 0 wt.% to 20 wt.%. The size of Fe nanoparticles is similar to 40 nm while the Fe(50)Ni(50) nanoparticles are similar to 20 nm in size. The Fe and Fe(50)Ni(50) nanoparticles dispersed composites are found to be ferromagnetic at room temperature both in the as-prepared and heat treated conditions with clear coercive fields of 5.5-35 x 10(3) A m(-1). The saturation magnetization increases by orders of magnitude on heat treatment, for e.g. from < 1.0 emu g(-1) to 143.4 emu g(-1) for Fe-15 wt.% Al(2)O(3) and 95.6 emu g(-1) for Fe(50)Ni(50)-15 wt.% Al(2)O(3). The Fe-composites exhibit a Curie transition at similar to 1000 K while the Fe(50)Ni(50) composites exhibit a transition at 880 K, both temperatures close to bulk values. (c) 2009
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Publisher |
ELSEVIER SCIENCE SA
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Date |
2011-07-28T11:55:24Z
2011-12-26T12:59:17Z 2011-12-27T05:50:25Z 2011-07-28T11:55:24Z 2011-12-26T12:59:17Z 2011-12-27T05:50:25Z 2009 |
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Type |
Article
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Identifier |
JOURNAL OF ALLOYS AND COMPOUNDS, 482(1-2), 155-159
0925-8388 http://dx.doi.org/10.1016/j.jallcom.2009.03.149 http://dspace.library.iitb.ac.in/xmlui/handle/10054/7394 http://hdl.handle.net/10054/7394 |
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Language |
en
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