Size dependence of the magnetic properties of Ni nanoparticles prepared by thermal decomposition method

Xuemin He, Wei Zhong*, Chak Tong AU, Youwei Du

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

81 Citations (Scopus)

Abstract

By means of thermal decomposition, we prepared single-phase spherical Ni nanoparticles (23 to 114 nm in diameter) that are face-centered cubic in structure. The magnetic properties of the Ni nanoparticles were experimentally as well as theoretically investigated as a function of particle size. By means of thermogravimetric/differential thermal analysis, the Curie temperature TC of the 23-, 45-, 80-, and 114-nm Ni particles was found to be 335°C, 346°C, 351°C, and 354°C, respectively. Based on the size-and-shape dependence model of cohesive energy, a theoretical model is proposed to explain the size dependence of TC. The measurement of magnetic hysteresis loop reveals that the saturation magnetization MS and remanent magnetization increase and the coercivity decreases monotonously with increasing particle size, indicating a distinct size effect. By adopting a simplified theoretical model, we obtained MS values that are in good agreement with the experimental ones. Furthermore, with increase of surface-to-volume ratio of Ni nanoparticles due to decrease of particle size, there is increase of the percentage of magnetically inactive layer.

Original languageEnglish
JournalNanoscale Research Letters
Volume8
Issue number1
DOIs
Publication statusPublished - 2013

Scopus Subject Areas

  • Materials Science(all)
  • Condensed Matter Physics

User-Defined Keywords

  • Cohesive energy
  • Curie temperature
  • Magnetically inactive layer
  • Size dependence

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