Preparation of Dy-ferrite ferrofluids and magnetochemical studies on the superparamagnetism

Citation
Xl. Hu et al., Preparation of Dy-ferrite ferrofluids and magnetochemical studies on the superparamagnetism, CHIN J CHEM, 19(8), 2001, pp. 733-737
Citations number
9
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Chemistry
Journal title
CHINESE JOURNAL OF CHEMISTRY
ISSN journal
1001-604X → ACNP
Volume
19
Issue
8
Year of publication
2001
Pages
733 - 737
Database
ISI
SICI code
1001-604X(200108)19:8<733:PODFAM>2.0.ZU;2-W
Abstract
This paper reports unprecedented preparation of Dy-ferrite water-based ferr ofluids stabilized by polymeric surfactant PMAA. The stability of ferroflui ds was characterized in terms of the equation of criterion for the stabilit y of ferrofluids. Magnetic susceptibility was measured with a Faraday-type magnetic balance at different temperature and with different magnetic field intensity. According to the Langevin function, superparamagnetism of Dy-fe rrite ferrofluids has been confirmed by the curves of saturation magnetizat ion a versus HI T, and the blocking temperature is between 160 and 200 K. I n terms of the simplified Langevin function in the low magnetic field, the average particle size is 20 urn that coincides with the result evaluated by FHMW. In addition, chemical analysis, infrared spectra and Mossbauer spect roscopy were utilized to analyze the main components of the ferrofluids.