Magnetic Properties of Colloidal Suspensions of Interacting Magnetic Particles

Abstract

We review equilibrium thermodynamic properties of systems of magnetic particles like ferrofluids in which dipolar interactions play an important role. The review is focussed on two subjects: (i) the magnetization with the initial magnetic susceptibility as a special case and (ii) the phase transition behavior. Here the condensation ("gas/liquid") transition in the subsystem of the suspended particles is treated as well as the isotropic/ferromagnetic transition to a state with spontaneously generated long-range magnetic order.

Study of magnetisation behaviours for binary ionic ferrofluids

“…While ¼ 0, formula (7) is just formula (6). From Figure 5, it can be seen that Langevin theoretical curve has a consideration deviation with the experimental result, but the model of gas-like compression ( ¼ 12, the error is estimate at AE1) fits the experimental result very well.…”

“…The relationship between the saturation magnetisation of ferrofluid and the particle is regarded as M f ¼ M p [6]. But, for the CoFe 2 O 4 system, M f (¼0.95 kA m À1 ) is less than M p (¼1.32 kA m À1 ).…”

“…where 0 is the vacuum permeability, r ij is the particles' distance, i and j are the angles between orient of the moments and central connections line [6]. Figure 6.…”

“…Ferromagnetism or ferrimagnetism nanoparticles have an inherent magnetic moment: in Equation (1), M is the saturation magnetisation M s [6]. Paramagnetic particles have an induced magnetic moment: M is expressed by B, where is susceptibility and B is the magnetic field strength [7].…”

Modelling of magnetic hyperfine field in nanoparticles

“…Magnetic nanostructures and nanoparticles have recently been intensively studied [1,2]. The nanosized materials have different properties compared with the bulk materials.…”