Рубрики:
OLEIC-ACID
CATALYST
HYPERTHERMIA
PARTICLES
OXIDATION
REMOVAL
CO
Кл.слова (ненормированные):
Magnetic materials -- Magnetic properties -- Precipitation -- Electron paramagnetic resonance
OLEIC-ACID
CATALYST
HYPERTHERMIA
PARTICLES
OXIDATION
REMOVAL
CO
Кл.слова (ненормированные):
Magnetic materials -- Magnetic properties -- Precipitation -- Electron paramagnetic resonance
Аннотация: A one-pot synthesis method for the controllable growth of magnetite nanoparticles directly during the process of co-precipitation using citrate ions was developed. The effects of the concentration of citrate ions and the solution pH on the characteristics of magnetite particles with sizes in the range of 4-10 nm synthesized by the method of co-precipitation were studied. The results showed that the specified concentration of citrate ions allowed the preparation of magnetite particles with a definite size that exhibited superparamagnetic behaviour in a particular temperature range. As the concentration ratio of citrate to iron ions was increased from 0 to 0.11, the average size of the prepared magnetite particles decreased from 10.5 to 4.4 nm. As a result, the superparamagnetic blocking temperature decreased from 300 to 20 K, the saturation magnetisation decreased from 50 to 20 emu g(-1), and the average magnetic moment decreased from 8000 mu(B) to 340 mu(B) (at T = 300 K). The obtained experimental data proved that the size effects of the magnetite nanoparticles can be attributed to the capping of the magnetite surface by adsorbed citrate ions. Thus, the suggested approach allows magnetite nanoparticles to be prepared with an optimum particle size around superparamagnetic threshold that prevents their irreversible agglomeration and simultaneously allows them to be removed from a solution at an acceptable rate. (C) 2014 Elsevier B.V. All rights reserved.
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Держатели документа:
Russian Acad Sci, Siberian Branch, Boreskov Inst Catalysis, Novosibirsk 630090, Russia
Russian Acad Sci, Siberian Branch, LV Kirensky Phys Inst, Krasnoyarsk 660036, Russia
Доп.точки доступа:
Kirillov, V. L.; Balaev, D. A.; Балаев, Дмитрий Александрович; Semenov, S. V.; Семёнов, Сергей Васильевич; Shaikhutdinov, K. A.; Шайхутдинов, Кирилл Александрович; Martyanov, O. N.; Siberian Branch of the Russian Academy of Sciences