Magnetic measurements as a key to the particle size distribution in ferrofluids: Experiment, theory and computer simulations

In the present paper, we show the way of finding a particle-size distribution from the experimental magnetization curves for a polydisperse magnetite ferrofluid at various concentrations using the modified mean-field theory of the second order (MMF2). We check the validity of the obtained distribution by computer simulations. To check for consistency, extensive molecular dynamics and Monte Carlo simulations are performed for systems with a discretized version of particle-size distribution p(x) corresponding as closely as possible to that of the real ferrofluid. Essentially perfect agreement between experiment, theory, and computer simulation is demonstrated, thus, proving the MMF2 theory to be an effective tool for the magnetogranulometric analysis for the ferrofluids with a wide range of concentrations.