The extrinsic hysteresis behavior of dilute binary ferrofluids

• Published in: The European physical journal. E, Soft matter and biological physics Vol. 37; no. 10; p. 102
• Main Authors: Lin, Lihua, Li, Jian, Lin, Yueqiang, Liu, Xiaodong, Chen, Longlong, Li, Junming, Li, Decai
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.10.2014; EDP Sciences
• Subjects: Biological and Medical Physics; Biophysics; Chemistry; Colloidal state and disperse state; Complex Fluids and Microfluidics; Complex Systems; Exact sciences and technology; General and physical chemistry; Nanotechnology; Physical and chemical studies. Granulometry. Electrokinetic phenomena; Physics; Physics and Astronomy; Polymer Sciences; Regular Article; Soft and Granular Matter; Surfaces and Interfaces; Thin Films; Soft Matter: Colloids and Nanoparticles; Iron oxide; Magnetization; Nanoparticle; Transition element compounds; Hysteresis; Nickel oxide; Magnetic properties
• ISSN: 1292-8941; 1292-895X
• DOI: 10.1140/epje/i2014-14102-6

. We report on the magnetization behavior of dilute binary ferrofluids based on - Fe 2 O 3 /Ni 2 O 3 composite nanoparticles (A particles), with diameter about 11nm, and ferrihydrite ( Fe 5 O 7 (OH) · 4H 2 O nanoparticles (B particles), with diameter about 6 nm. The results show that for the binary ferrofluids with A-particle volume fraction = 0.2 % and B-particle volume fractions = 0.1 % and = 0.6 %, the magnetization curves exhibit quasi-magnetic hysteresis behavior. The demagnetizing curves coincide with the magnetizing curves at high fields. However, for single - Fe 2 O 3 /Ni 2 O 3 ferrofluids with = 0.2 % and binary ferrofluids with = 0.2 % and = 1.0 %, the magnetization curves do not behave in this way. Additionally, at high field (750 kA/m), the binary ferrofluid with = 1.0 % has the smallest magnetization. From the model-of-chain theory, the extrinsic hysteresis behavior of these samples is attributed to the field-induced effects of pre-existing A particle chains, which involve both Brownian rotation of the chains’ moments and a Néel rotation of the particles’ moments in the chains. The loss of magnetization for the ferrofluids with = 1.0 % is attributed to pre-existing ring-like A-particle aggregates. These magnetization behaviors of the dilute binary ferrofluids not only depend on features of the strongly magnetic A-particle system, but also modifications of the weaker magnetic B-particle system. Graphical abstract