کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
10714004 1025564 2012 5 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
The quasi-magnetic-hysteresis behavior of polydisperse ferrofluids with small coupling constant
موضوعات مرتبط
مهندسی و علوم پایه فیزیک و نجوم فیزیک ماده چگال
پیش نمایش صفحه اول مقاله
The quasi-magnetic-hysteresis behavior of polydisperse ferrofluids with small coupling constant
چکیده انگلیسی
The magnetization behaviors of ferrofluids based on γ-Fe2O3/Ni2O3 composite nanoparticles of size about 11 nm have been investigated. The dipole coupling constant λ of these particles is so small (0.43) that they cannot form aggregates through magnetic interaction alone. Experimental results have shown that for a polydisperse ferrofluid with a particle volume fraction of ϕV=2.4%, the magnetization curve exhibits quasi-magnetic-hysteresis behavior, i.e., the demagnetization curve lies above the magnetization curve in a high field. However, for a more dilute γ-Fe2O3/Ni2O3 ferrofluid with ϕV=0.94%, the magnetization curve does not show such behavior. According to the bidisperse model for polydisperse ferrofluids, these magnetization behaviors may be attributed to field-induced effects of self-assembled pre-existing chain-like aggregates. For such pre-existing chain-like aggregates, the orientation of the moments inside the particles is not co-linear, so that during the magnetization and demagnetization processes, their apparent magnetizations at the high-field limit are different. As a consequence, the magnetization curve of the ferrofluid with ϕV=2.4% displays quasi-magnetic-hysteresis.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Physica B: Condensed Matter - Volume 407, Issue 24, 15 December 2012, Pages 4638-4642
نویسندگان
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