Magnetization and susceptibility of polydisperse ferrofluids

TL;DR

This paper develops an analytical model for the magnetization of polydisperse ferrofluids using the mean spherical approximation and validates it with Monte Carlo simulations and experimental data.

Contribution

It introduces a new analytical expression for magnetization in polydisperse ferrofluids considering size distribution, validated against simulations and experiments.

Findings

Quantitative agreement with Monte Carlo simulation data.

Good correlation with experimental magnetization data.

Accurate prediction of initial susceptibility.

Abstract

On the basis of the mean spherical approximation of multicomponent dipolar hard sphere mixtures an analytical expression is proposed for the magnetic field dependence of the magnetization of size polydisperse ferrofluids. The polydispersity of the particle diameter is described by the gamma distribution function. Canonical ensemble Monte Carlo simulations have been performed in order to test these theoretical results for the initial susceptibility and the magnetization. The results for the magnetic properties of the polydisperse systems turn out to be in quantitative agreement with our present simulation data. In addition, we find good agreement between our theory and experimental data for magnetite-based ferrofluids.