Electronic structure and magnetic properties of GdM2 compounds

The formation of chain-like aggregates is studied theoretically on the basis of the model bidisperse ferrofluid, consisting of two fractions of small and large particles. Various topological structures of chains, containing particles of both fractions, are considered. The equilibrium chain distribution is obtained with the help of density functional approach. This model results are evidence of the fact that in spite of the small particle magnetic moment value being low, the presence of the latter fraction exerts a considerable influence on the ferrofluid microstructure. The chain aggregate structure appearance probabilities are calculated and the phase diagram allowing one to find the most probable chain structure in real ferrofluid, knowing only the continuous particle size distribution, is built. (C) 2002 Published by Elsevier. Science B.V.