Magnetization of immobilized multi-core particles with varying internal structures.

This work is devoted to the study of the static magnetization of immobilized multi-core particles (MCPs) and their ensembles. These objects model aggregates of superparamagnetic nanoparticles that are taken up by biological cells and subsequently used, for example, as magnetoactive agents for cell imaging. In this study, we derive an analytical formula that allows us to predict the static magnetization of MCPs consisting of immobilized granules, in which the magnetic moment rotates freely the Néel mechanism.

Effect of Polydispersity on the Structural and Magnetic Properties of a Magnetopolymer Composite.

When using magnetopolymer composites in high-precision industrial and biomedical technologies, the problem of predicting their properties in an external magnetic field arises. In this work, we study theoretically the influence of the polydispersity of a magnetic filler on a composite's equilibrium magnetization and on the orientational texturing of magnetic particles formed during polymerization. The results are obtained using rigorous methods of statistical mechanics and Monte Carlo computer simulations in the framework the bidisperse approximation.

Structure and magnetization of a magnetoactive ferrocomposite.

This work is devoted to the theoretical study of the structural and magnetic properties of an ensemble of single-domain interacting magnetic nanoparticles immobilized in a non-magnetic medium. This model is typical for describing magnetically active soft materials, "smart" polymer ferrocomposites, which have been applied in science-intensive industrial and biomedical technologies. It is assumed that the ferrocomposite is obtained by solidification of the carrier medium in a ferrofluid under an external magnetic field, the intensity of which is determined by the Langevin parameter ; after the solidification of the carrier liquid, the nanoparticles retain the spatial distribution and orientation of their easy magnetization axes.

Magnetic properties of textured ferrocomposite consisting of immobilized superparamagnetic nanoparticles.

Wide use of magnetic nanoparticles in modern technologies and biomedical applications requires reliable theoretical models capable of predicting physical properties. Solidification of a ferroparticle suspension under the action of permanent magnetic field allows us to obtain a ferrocomposite, characterized by some orientational texture of the nanoparticle easy magnetization axes. The static magnetic response of this ferrocomposite differs from that of the parent magnetic suspension due to "freezing" of nanoparticle translational and rotational degrees of freedom.

Theory of static magnetization of magnetopolymer composites: The second virial approximation.

This paper deals with a theoretical study of the static magnetization of a composite, consisting of nanodisperse single-domain ferromagnetic particles immobilized in a nonmagnetic medium. This situation is typical for magnetopolymer systems-smart materials, which found applications in high industrial and biomedical applications. It is supposed that the composite was polymerized without an external magnetic field; after curing the particles retain the spatial distribution and orientation of their axes of easy magnetization that they had before the host medium polymerization.

Modified mean-field theory of the magnetic properties of concentrated, high-susceptibility, polydisperse ferrofluids.

The effects of particle-size polydispersity on the magnetostatic properties of concentrated ferrofluids are studied using theory and computer simulation. The second-order modified mean-field (MMF2) theory of Ivanov and Kuznetsova [Phys. Rev.

The initial magnetic susceptibility of polydisperse ferrofluids: A comparison between experiment and theory over a wide range of concentration.

Temperature dependencies of the static initial magnetic susceptibility for ferrofluids at various concentrations are studied using experiment and statistical-mechanical theories. Magnetic susceptibility measurements are carried out for twelve samples of magnetite-based fluids stabilized with oleic acid over a wide range of temperatures (210 K ≲T ≲ 390 K); all samples have the same granulometric composition but different volume ferroparticle concentrations (0.2 ≲ φ ≲ 0.