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).

Torchio, R., Meneghini, C., Mobilio, S., Capellini, G., Garcıa, A., Prieto, J., et al. (2010). Magnetic properties of colloidal cobalt nanoclusters. JOURNAL OF PHYSICS. CONFERENCE SERIES, 200(200), 072100-072103 [10.1088/1742-6596/200/7/072100].

Magnetic properties of colloidal cobalt nanoclusters

TURCO LIVERI, Vincenzo;RUGGIRELLO, Angela Monia;
2010

Abstract

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).
Settore CHIM/02 - Chimica Fisica
Torchio, R., Meneghini, C., Mobilio, S., Capellini, G., Garcıa, A., Prieto, J., et al. (2010). Magnetic properties of colloidal cobalt nanoclusters. JOURNAL OF PHYSICS. CONFERENCE SERIES, 200(200), 072100-072103 [10.1088/1742-6596/200/7/072100].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10447/50909
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