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

He X, Zhong W, Au CT, Du Y - Nanoscale Res Lett (2013)

Bottom Line: 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.

View Article: PubMed Central - HTML - PubMed

Affiliation: National Laboratory of Solid State Microstructures and Jiangsu Provincial Laboratory for NanoTechnology, Department of Physics, Nanjing University, Nanjing 210093, China. wzhong@nju.edu.cn.

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.

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Size dependence of Curie temperature. Based on the TG/DTA experimental results (solid circles) and that of theoretical calculation (red solid line).
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Figure 5: Size dependence of Curie temperature. Based on the TG/DTA experimental results (solid circles) and that of theoretical calculation (red solid line).

Mentions: The TC value decreases with the decrease of particle size (see the solid circles in Figure 5), showing a strong size effect. In theory, the cohesive energy En of free-standing nanoparticles with random shape can be described as [33]


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

He X, Zhong W, Au CT, Du Y - Nanoscale Res Lett (2013)

Size dependence of Curie temperature. Based on the TG/DTA experimental results (solid circles) and that of theoretical calculation (red solid line).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4231360&req=5

Figure 5: Size dependence of Curie temperature. Based on the TG/DTA experimental results (solid circles) and that of theoretical calculation (red solid line).
Mentions: The TC value decreases with the decrease of particle size (see the solid circles in Figure 5), showing a strong size effect. In theory, the cohesive energy En of free-standing nanoparticles with random shape can be described as [33]

Bottom Line: 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.

View Article: PubMed Central - HTML - PubMed

Affiliation: National Laboratory of Solid State Microstructures and Jiangsu Provincial Laboratory for NanoTechnology, Department of Physics, Nanjing University, Nanjing 210093, China. wzhong@nju.edu.cn.

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.

No MeSH data available.


Related in: MedlinePlus