Co nanoclusters were synthesized by an inverse-micelle chemical route. The magnetic and microstructural properties of the nanoparticles have been analyzed as a function of the surfactant (AOT and DEHP) and the drying method. Microstructural analysis has been performed by TEM and XANES; magnetic properties have been studied by hysteresis loops and zero-field cooling – field cooling (ZFC-FC) curves. TEM images show 2 to 4 nm sized particles spherical in shape. XANES measurements point out a significant presence of Co3O4with metallic Co and some Co2+ bound to the surfactant. The presence of antiferromagnetic Co3O4 explains the magnetic transition observed at low T in both ZFC-FC measurements and hysteresis loops. Finally, the presence of magnetic interactions explains the bigger effective cluster size obtained from hysteresis loops fits (6-10 nm) compared to the sizes observed by TEM (2-4 nm).
R. TORCHIO, MENEGHINI C, S. MOBILIO, G. CAPELLINI, A. GARCIA PRIETO, J. ALONSO, et al. (2010). Magnetic properties of colloidal cobalt nanoclusters. JOURNAL OF PHYSICS. CONFERENCE SERIES, 200, 072100-072104.
Titolo: | Magnetic properties of colloidal cobalt nanoclusters |
Autori: | |
Data di pubblicazione: | 2010 |
Rivista: | |
Citazione: | R. TORCHIO, MENEGHINI C, S. MOBILIO, G. CAPELLINI, A. GARCIA PRIETO, J. ALONSO, et al. (2010). Magnetic properties of colloidal cobalt nanoclusters. JOURNAL OF PHYSICS. CONFERENCE SERIES, 200, 072100-072104. |
Abstract: | Co nanoclusters were synthesized by an inverse-micelle chemical route. The magnetic and microstructural properties of the nanoparticles have been analyzed as a function of the surfactant (AOT and DEHP) and the drying method. Microstructural analysis has been performed by TEM and XANES; magnetic properties have been studied by hysteresis loops and zero-field cooling – field cooling (ZFC-FC) curves. TEM images show 2 to 4 nm sized particles spherical in shape. XANES measurements point out a significant presence of Co3O4with metallic Co and some Co2+ bound to the surfactant. The presence of antiferromagnetic Co3O4 explains the magnetic transition observed at low T in both ZFC-FC measurements and hysteresis loops. Finally, the presence of magnetic interactions explains the bigger effective cluster size obtained from hysteresis loops fits (6-10 nm) compared to the sizes observed by TEM (2-4 nm). |
Handle: | http://hdl.handle.net/11590/119195 |
Appare nelle tipologie: | 1.1 Articolo in rivista |