Molecular models to investigate diamagnetic anisotropy: Towards the directed synthesis of rare-earth free permanent magnets

The development of new permanent magnets without rare-earth metals requires a paradigm shift in the area of magnetic anisotropy. We are taking the novel approach of conferring magnetic anisotropy from a diamagnetic element to a paramagnetic element through a covalent interaction, thereby separating the magnetic moment into one atom for spin and a separate atom for orbital moment. Heavy diamagnetic elements have significant spin-orbit coupling due to their large atomic number, yet formally have no orbital moment because they are diamagnetic. Harnessing this magnetic anisotropy by creating a covalent interaction with a spin carrier will allow us to develop a new class of magnetically anisotropic materials with main group elements as the source of magnetic anisotropy. Towards those ends, we will synthesize new bimetallic organometallic molecules and study whether heavy elements such as bismuth can confer magnetic anisotropy through a mechanism we term “diamagnetic anisotropy”. Our molecular systems will serve to test our hypothesis and inform our future synthesis of permanent magnets. The development of a new form of a magnetic anisotropy will create a replacement for rare-earth based magnets.