Thermodynamics of bidisperse ferrofluids in the absence of external magnetic field

A. Yu. Solov'yeva - E. A. Elfimova

Institute of Mathematics and Computer Sciences, Ural Federal University, 51 Lenin ave., Ekaterinburg 620000, Russia

Abstract
Thermodynamic properties of ferrofluids are studied using theory and simulations. A bidisperse dipolar hard sphere model of ferrofluid is studied in detail. A virial expansion theory is constructed for Helmholtz free energy and thermodynamic functions, such as heat capacity, pressure, and compressibility factor. A detailed comparison is made between theoretical predictions and accurate simulation data, and it is found that the theory works well for realistic values of the dipolar coupling constants, total volume concentration ϕ\leqslant 0.3, and for volume fractions of large particles  ∼ 10% and  ∼ 20% in the system. Tables 1, Figs 6, Refs 28.