High‐Spin Molecules with Magnetic Anisotropy toward Single‐Molecule Magnets

High‐spin molecules with easy‐axis magnetic anisotropy show slow magnetic relaxation of spin‐flipping along the axis of magnetic anisotropy and are called single‐molecule magnets (SMMs). SMMs behave as molecular‐size permanent magnets at low temperature and magnetic relaxation occurs by quantum tunneling processes; such molecules are promising candidates for use in quantum devices. We first discuss intramolecular ferromagnetic interactions for preparing high‐spin molecules. Second, we determine the magnetic anisotropy for single metal ions with dnconfigurations and discuss how molecular anisotropy arises from single‐ion anisotropy of the assembled component metal ions.