Magnetic relaxation in molecular nanostructures

Abstract Molecular magnetic materials present a wide range of magnetic relaxation phenomena. In particular, the chemists bottom-up approach to build molecular nanostructures provided this field with some unprecedented model systems, as the quasi isolated nanomagnets Mn 12 and Fe 8 , ferrimagnetic chains and planar structure with high anisotropy presenting very slow relaxation, and also several disordered systems with glassy behavior. In this paper we will review some aspects of magnetic relaxation, in particular thermally activated quantum tunneling in nanomagnets, as well as its influence in specific heat experiments. The dynamics of low-dimensional magnetic molecular systems and the similarity with spin glasses will also be discussed.