Preparation of Dy-ferrite Ferrofluids and Magnetochemical Studies on the Superparamagnetism

• 来源期刊: 中国化学（英文版）
• 学科: 化学
• 年，卷（期）: 2001,（8）
• 所属期刊栏目: Articles
• 页码范围: 733-737
• 页数: 5页
• 分类号: O6
• 语种: 英文

摘要

This paper reports unprecedented preparation of Dy-ferrite water-based ferrofiuids stabilized by polymeric surfactant PMAA. The stability of ferrofluids was characterized in terms of the equation of criterion for the stability 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,superparamagtism of Dy-ferrite ferrofiuids has been confirmed by the curves of saturation magnetization σ versus H/T, and the blocking temperature is between 160 and 200 K.In terms of the simplified Langevin function in the low magnefic field, the average particle size is 20 nm that coincides with the result evaluated by FHMW. In addition, chemical analysis, infi-ared spect-a and Mosslauer spectroscopy were utilized to analyze the main components of the ferrofiuids.