Effect of interstitial oxygen on the crystal structure and magnetic properties of Ni nanoparticles
| Autor: | J. A. De Toro, Shanker Ram, Volety Srinivas, J. M. Riveiro, A. K. Roy |
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| Rok vydání: | 2004 |
| Předmět: | |
| Zdroj: | Journal of Applied Physics. 96:6782-6788 |
| ISSN: | 1089-7550 0021-8979 |
| DOI: | 10.1063/1.1792809 |
| Popis: | The structure and magnetic properties of fine Ni nanoparticles (∼65nm diameter) having a spontaneous surface oxide layer have been studied. The particles were prepared by the chemical reduction of nickel ions in an aqueous medium, with sodium borohydride as the reducing agent. X-ray diffraction (XRD), transmission electron microscopy, and magnetization measurements (M-H plots and field cooled∕zero field cooled curves) have been used for characterizing the samples. No detectable change is observed in the M-H curves or in the XRD patterns of the “as prepared” sample and the sample annealed in air at 573K. We have indexed both these patterns as Ni in a tetragonal crystal structure with lattice parameters a=0.4905nm, c=0.5330nm and a=0.4890nm, c=0.5310nm for the “as prepared” and 573K annealed sample, respectively. This is a new report about the formation of Ni in a modified crystal structure. The M-H curves of both the samples show a clear hysteretic behavior but do not saturate, thereby suggesting the exist... |
| Databáze: | OpenAIRE |
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