Park, IW Yoon, M Kim, YM Kim, Y Yoon, H Song, HJ Volkov, V Avilov, A Park, YJ 2024-01-21T09:02:13Z 2024-01-21T09:02:13Z 2021-09-03 2003-05 0038-1098 https://pubs.kist.re.kr/handle/201004/138609 Superparamagnetic properties of self-aggregated cobalt nanoparticles in the perfluorinated sulfo-cation membrane (MF-4SK) prepared by ion-exchange method were investigated by transmission electron microscopy (TEM) and superconducting quantum interference device (SQUID) magnetometry at various temperatures. Our experimental results show that cobalt nanoparticles in MF-4SK exhibit superparamagnetic properties above the blocking temperature (T-B), which varies from similar to 80 to similar to 300 K depending on the cobalt concentration at 100 Oe applied field. The average particle radius of 3.8 nm inferred from Langevin function fit for the concentration of 7.8 x 10(19) cobalt atoms per 1 g of polymer film is in good agreement with TEM observation. This experimental evidence suggests that cobalt nanoparticles in the polymer film obey a single-domain theory. The results are discussed in the light of current theory for the superparamagnetic behavior of magnetic nanoparticles. (C) 2003 Elsevier Science Ltd. All rights reserved. English PERGAMON-ELSEVIER SCIENCE LTD SUPERPARAMAGNETIC PROPERTIES PARTICLES RELAXATION CO Magnetic properties and microstructure of cobalt nanoparticles in a polymer film Article 10.1016/S0038-1098(03)00189-3 1 SOLID STATE COMMUNICATIONS, v.126, no.7, pp.385 - 389 SOLID STATE COMMUNICATIONS 126 7 385 389 scie scopus 000182779100005 2-s2.0-0037405004 Physics, Condensed Matter Physics Article SUPERPARAMAGNETIC PROPERTIES PARTICLES RELAXATION CO nanoparticles blocking temperature superparamagnetism