Interparticle correlations and magnetic properties of concentrated ferrocolloids

A statistical mechanical model was proposed for describing magnetic properties of highly concentrated ferrocolloids and dielectric properties of polar liquids. The model is based on a relationship between the magnetization and the pair correlation function of a spatially homogeneous ferroparticle system. The advantage of the proposed method is that the determination of the pair distribution function, with an accuracy of the powers of the concentration n(k) and the powers of the interparticle dipole-dipole interaction potential U-d(k), leads to an expression for the magnetization of the order of n(k + 1) and U-d(k + 1), respectively. Relations for the magnetization and the magnetic susceptibility of a ferrofluid and also for the permittivity of a polar liquid taking into account interparticle correlations with an accuracy of terms similar to U-d(2) were derived. The results obtained within the framework of this model agree closely with the numerical calculations and experimental data.