Single chain magnets: where to from here?

Single chain magnets (SCMs) are an interesting class of molecular polymeric materials displaying slow relaxation of the magnetization. They provide, at low temperatures, a magnetic hysteretic behaviour for a single polymeric chain. Although their behaviour evokes better-known magnetic nanoparticles and single-molecule magnets (SMMs), the similarity is mainly apparent. The fundamental differences in the physical origin of the magnetic behaviour offer perspectives that are still largely unexplored. Here we review the progress made in the synthesis, characterization and theoretical understanding of SCMs, highlighting differences and similarities with SMMs. For each of the points we then present a perspective of the advantages offered by this class of materials and we point out the main aspects that remain to be developed in the field.