The structure of ferrofluids: A status report

We review the recent advances in our understanding of the behavior of ferrofluids that occurred during the last 5 years. Ferrofluids can be viewed as a particular interesting class of dipolar fluids, which have a wide range of potential application in biomedicine and technology that is responsible for the fast growing number of research papers in this area. We will concentrate on the issues of phase behavior and microstructure formation with and without an externally applied magnetic field. In addition we discuss the influence of polydispersity that is an almost unavoidable feature of any real ferrofluid. We will focus on the theoretical aspects of those issues, however, we tried also to discuss new results coming from experiments and relate them to our current theoretical understanding of ferrofluids.