Structure and magnetic properties of mono- and bi-dispersed ferrofluids as revealed by simulations

The magneto-optical behaviors modulated by unaggregated system for γ-Fe2O3–ZnFe2O4 binary ferrofluids

“…Thus, since the number of chained particles was approximately independent of the applied magnetic field, the average length of the chains increased linearly with the applied magnetic field, 33 thus increasing n and k. In addition, in the bi-dispersed system of γ -Fe 2 O 3 -ZnFe 2 O 4 binary ferrofluids, a few unchained ZnFe 2 O 4 particles would have stuck to the edges of the chains formed by the chained γ -Fe 2 O 3 particles. This sticking also resulted from weak van der Waals forces, so the chains formed from unchained particles were relatively unstable, and the further aggregation of the shorter γ -Fe 2 O 3 clusters into long chains was prevented; 34,35 i.e., the reduction in chain length was caused by the unchained ZnFe 2 O 4 particles. The sticking action can be viewed as weakening the dipoledipole interaction potential between the chained γ -Fe 2 O 3 particles in the medium of the unchained ZnFe 2 O 4 particles.…”

“…12,32,35). This caused the γ -Fe 2 O 3 particle chains in the binary ferrofluids to be shorter than those in the pure γ -Fe 2 O 3 ferrofluid.…”

Study of magnetisation behaviours for binary ionic ferrofluids

“…Polydispersity of ferrofluids appears naturally since the particles in real ferrofluids always possess a size distribution. In recent years, a bidisperse theoretical model which contains the large and small two size's particles with the same chemical composition is advanced [1][2][3][4][5]. It has been concluded that the large particles constitute the main structure of the ferrofluids under an external magnetic field, and the small particles depending on relative content either suppress or enhance the formation and variation of field-induced structure.…”

Study of coercive force foryZnFe2O4–(1 −y)CoFe2O4magnetic nanoparticles system

“…In disperse systems (such as ferrofluids), the interaction of magnetic nanoparticles that affects magnetisation has been studied in both theory and experiment by many researchers and many models have been put forward, but a unified understanding of their mechanism has not yet been achieved [1][2][3][4][5][6]. There is distribution of particles size in the real ferrofluids, and it is a polydispersed system [7]. The properties of ferrofluids (magnetic property, microstructurer, viscosity and so on) are different from those of a monodispersed system, and there are many difficulties in discussing the mechanism on the properties.…”

“…The properties of ferrofluids (magnetic property, microstructurer, viscosity and so on) are different from those of a monodispersed system, and there are many difficulties in discussing the mechanism on the properties. In recent years, there have been a few theoretical researches into bidispersed systems consisting of large and small size particles without size distribution [7][8][9][10], but such a system is hard to achieve in experiment. The magnetic moment m of single domain particles is proportional to volume V and the magnetic moment m of spherical particles can be expressed as:…”