Condensation phase transitions in ferrofluids

We present the results of theoretical study of a new scenario of condensation phase transitions in ensemble of particles in ferrofluids. In this scenario the phase transition begins with the formation of linear chainlike clusters which collapse into dense globules when a number of particles in the chain exceeds a certain magnitude nc. These globules serve as nuclei of a new dense phase. Final (equilibrium) stage of the phase transition is also considered. Our estimates show that for actual parameters of ferrofluid without magnetic field nc is about 50–90. Calculated magnetic volume concentration of particles in dense phase after separation is about 0.2; initial susceptibility of the dense phase is 70–140. These results are in agreement with known computer and laboratory experiments.