Preparation of PMAA-coated Dysprosium Ferrite Ferrofluids and Study on the Superparamagnetism  

作　　者：ZHU Chuan-zheng SHEN Qin HU Xian-luo ZHANG Jie ZHAO Hong 

机构地区：[1]Department of Chemistry,East China Normal University,Shanghai 200062,P.R.China

出　　处：《Chemical Research in Chinese Universities》2002年第1期30-33,共4页高等学校化学研究(英文版)

基　　金：Supported by the National Natural Science Foundation of China(No.2 97730 14)

摘　　要：The present paper covers the unprecedented preparation of stable aqueous Dy-ferrite ferrofluids, whereby colloidal Dy_ δ Fe_ 3- δ O_4 ultrafine particles were dispersed by using polymeric surfactant PMAA. The stabilities of the series of the ferrofluids were studied according to the stability indexes. The susceptibility measurements were made with a Farady-type magnetic balance at various temperatures and magnetic field intensities. In terms of Langevin function, the σ versus H/T curves showed that Dy-ferrite ferrofluids exhibited superparamagnetism behavior and the blocking temperatures were in the range from 160 to 200 K. Moreover, the ferrofluids were characterized by means of Infra-red spectroscopy, transmission electron microscopy, X-ray diffraction, and Mssbauer spectroscopy.The present paper covers the unprecedented preparation of stable aqueous Dy-ferrite ferrofluids, whereby colloidal Dy_ δ Fe_ 3- δ O_4 ultrafine particles were dispersed by using polymeric surfactant PMAA. The stabilities of the series of the ferrofluids were studied according to the stability indexes. The susceptibility measurements were made with a Farady-type magnetic balance at various temperatures and magnetic field intensities. In terms of Langevin function, the σ versus H/T curves showed that Dy-ferrite ferrofluids exhibited superparamagnetism behavior and the blocking temperatures were in the range from 160 to 200 K. Moreover, the ferrofluids were characterized by means of Infra-red spectroscopy, transmission electron microscopy, X-ray diffraction, and Mssbauer spectroscopy.

关 键 词：Dy-ferrite ferrofluid Susceptibility SUPERPARAMAGNETISM Stability PMAA 

分 类 号：TQ58[化学工程—精细化工]