Effect of hydrophobic coating on the magnetic anisotropy and radiofrequency heating of γ-Fe.sub.2./sub.O.sub.3./sub. nanoparticles

0397844 - FZÚ 2014 RIV NL eng J - Článek v odborném periodiku
Singh, M. - Ulbrich, P. - Prokopec, V. - Svoboda, P. - Šantavá, Eva - Štěpánek, F.
Effect of hydrophobic coating on the magnetic anisotropy and radiofrequency heating of γ-Fe₂O₃ nanoparticles.
Journal of Magnetism and Magnetic Materials. Roč. 339, AUG (2013), s. 106-113. ISSN 0304-8853. E-ISSN 1873-4766
Institucionální podpora: RVO:68378271
Klíčová slova: nanoparticle * maghemite * blocking temperature * superparamagnetism * saturation magnetization
Kód oboru RIV: BM - Fyzika pevných látek a magnetismus
Impakt faktor: 2.002, rok: 2013

Hydrophobic (oleic acid) coating effect on the magnetic properties of maghemite(γ-Fe2O3) nanoparticles investigated. Particles prepared by a novel bi-phasic co-precipitation way and their properties compared with uncoated particles and particles prepared by a standard single-phase way. Oleic acid coated particles had a mean diameter of 6nm when the two-phase precipitation procedure was used, compared to 12nm-nanoparticles prepared in a single phase under otherwise identical conditions. Super Quantum Interference Device measurements show superparamagnetism of the nanoparticles, with a saturation magnetization at 4K to be 66.4 emu/g and 89.0 emu/g for the coated nanoparticles obtained by two-and single-phase procedure, respectively. ZFC and FC curves reveal a dramatic shift in the blocking temp.of the coated particles,and a significant change in their anisotropy.Hydrophobic nanoparticles were able to form stable ferrofluids in a range of organic solvents and show good heating rates in a 400kHz alternating magnetic field.
Trvalý link: http://hdl.handle.net/11104/0225445