Ferrofluid clustering driven by dilution: An alternating current susceptibility investigation

作     者：Zhong, Jing Liu, Wenzhong Li, Yin Wu, Mian Morais, Paulo Cesar 

作者机构：Huazhong Univ Sci & Technol Dept Control Sci & Engn Wuhan 430074 Peoples R China Huazhong Univ Sci & Technol Key Lab Image Proc & Intelligent Control Wuhan 430074 Peoples R China Univ Brasilia Inst Fis BR-70910900 Brasilia DF Brazil 

出 版 物：《JOURNAL OF APPLIED PHYSICS》 (应用物理学杂志)

年 卷 期：2012年第111卷第6期

页      面：064317-064317页

核心收录：

学科分类：07[理学] 0702[理学-物理学] 

基　　金：NSFC [61174008, 11104089] MOST [0S2012GR0121] RD HB [2010BFA013] GBIE [HF09062011184] 

主　　题：magnetic fluids magnetic moments magnetic susceptibility magnetic transitions 

摘      要：The influence of sample dilution upon cluster disruption/formation within a ferrofluid sample is investigated by monitoring the temperature dependence of the initial AC susceptibility. The effective magnetic response of the ferrofluid sample is described by a combination of Langevin s functions modulated by the relative content of monomers and clusters. Deviations from the linearity found in the inverse susceptibility versus temperature (chi(-1) T) data were successfully described via the disruption of clusters into monomers within the approach of a second order phase transition at the critical temperature T*. We found T* increasing monotonically from 386 K to 412 K as the stock ferrofluid sample is diluted up to a factor of 5. In the same dilution range, we found the normalized relative content of clusters increasing from about 38% up to 42%, whereas the average effective magnetic moment of the clusters increased by a factor of 1.7. (C) 2012 American Institute of Physics. [http://***/10.1063/1.3697677]