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 Co3O4 with 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, C. MENEGHINI, S. MOBILIO, CAPELLINI G, A. GARCÍA PRIETO, J. ALONSO, et al. (2010). MAGNETIC PROPERTIES OF COLLOIDAL COBALT NANOCLUSTERS. In J. Phys.: Conf. Ser. 200 (pp.072100) [10.1088/1742-6596/200/7/072100].
Titolo: | MAGNETIC PROPERTIES OF COLLOIDAL COBALT NANOCLUSTERS | |
Autori: | ||
Data di pubblicazione: | 2010 | |
Citazione: | R. TORCHIO, C. MENEGHINI, S. MOBILIO, CAPELLINI G, A. GARCÍA PRIETO, J. ALONSO, et al. (2010). MAGNETIC PROPERTIES OF COLLOIDAL COBALT NANOCLUSTERS. In J. Phys.: Conf. Ser. 200 (pp.072100) [10.1088/1742-6596/200/7/072100]. | |
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 Co3O4 with 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/11590/172492 | |
Appare nelle tipologie: | 4.1 Contributo in Atti di convegno |