Magnetic particle–particle interaction in frozen magnetic fluids

Abstract

Magnetic resonance is used to study magnetic dipole particle–particle interaction in ionic water-based iron-manganese magnetic fluids. A set of six samples having particle concentration running from 1.2×1016 to 6.3×1016 particles/cm3 were frozen below room temperature and analyzed in the range of 100–250 K. Average values of magnetic particle–particle interaction energy were obtained from the temperature dependence of the resonance linewidth broadening. At 1.2×1016 particles/cm3 magnetic particle–particle interaction energy is found to be of the order of 1.2 meV. However, at 6.3×1016 particles/cm3 magnetic particle–particle interaction energy goes to 32 meV. The enhancement of the magnetic particle–particle interaction energy far beyond the linearity is associated to cluster structuration. A one-dimensional model for cluster structuration is presented.

Investigation of the Magnetic Anisotropy in Manganese Ferrite Nanoparticles Using Magnetic Resonance

“…Moderate particle concentration was used in both samples in order to avoid particle-particle interaction. The values However, remarkable changes in the magnetic behavior have been observed after removing the carrier fluid from a magwe obtained for the effective magnetic anisotropy are smaller than the reported values for the bulk over the entire range netic fluid sample, even taking into account changes in the particle-particle distance (15). This Communication introof temperatures analyzed and are strongly dependent on the particle size.…”

“…Powdered samples are comrequirements of the simple theoretical model discussed beposed of magnetic agglomerates, in which case the particlelow. In our case, such a condition can be reached with the particle interaction usually plays a very important role in magnetic fluid sample having particle concentrations up to determining some of the many properties of such nanopar-3 1 10 16 particle/cm 3 , cooled in an external magnetic field ticle-based systems, as for instance, the onset of low-energy greater than one tesla (15). In our experimental setup, the excitations associated with magnetic agglomerates (13).…”

Ferrofluids: Synthetic Strategies, Stabilization, Physicochemical Features, Characterization, and Applications

“…[212] A model for the overall interaction energy between two FF particles, that is, the sum of van der Waals attraction and steric repulsion, was given using the full Hamaker expression for cis-oleic acid-coated ferroparticles in hexadecane medium. [137] Both the isotropic interparticle interactions and the anisotropic dipolar magnetic interaction can be varied by tuning the ionic strength and the size of the NPs.…”

Investigation of the Anisotropy in Frozen Nickel Ferrite Ionic Magnetic Fluid Using Magnetic Resonance

“…Equation [6] describes the angular variation measurements in a broad range of temperature and will be used to fit our experimental data in order to obtain the temperature dependence of the effective anisotropy (K). The chemical synthesis of high-quality NiFe 2 O 4 based ionic magnetic fluid has been obtained only recently (9).…”

“…3 represent the best fit of the experimental data according to Eq. [6]. Equation [3] has been used to fit the angular dependence of the resonance field as well.…”