ACTA

Physical Properties of Magnetite Nanoparticles Covered by 11-Mercaptoundecanoic Acid

M. Timko^a, P. Kopčanský^a, M. Antalik^a, M. Simsikova^b, E. Valusova^a, M. Molcan^a and J. Kováč^a
^aInstitute of Experimental Physics, SAS, Watsonova 47, 040 01 Kosice, Slovakia
^bDepartment of Biochemistry, Faculty of Sciences UPJS, Moyzesova 11, 041 54 Kosice, Slovakia

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We have investigated the magnetic behavior of magnetite nanoparticles covered by the 11-mercaptoundecanoic acid around magnetite core prepared by a standard co-precipitation method. The particles show superparamagnetic behavior at room temperature, with transition to a blocked state at blocking temperature 91 K estimated from zero field cooled and field cooled at 500 Oe experiment. The hysteresis loop measured at 293 K showed magnetization 32.8 emu/g at 50 kOe without any coercivity. The mean particle size (7.1 nm) was determined by fitting a magnetization curve obtained at 295 K assuming a log-normal size distribution.

DOI: 10.12693/APhysPolA.121.1321
PACS numbers: 47.65.Cb, 85.70.-w, 75.30.Cr, 75.47.Lx