Slowed relaxation of the magnetism through dilution into paramagnetic mediums

Single molecule magnets (SMMs) represent the smallest magnetic domains (a single molecule) and as such have potential applications in information storage, quantum computing, and spintronics. Extending the lifetime of the magnetic relaxation is critical to applications of these molecules. Dilution of SMMs is a common strategy employed to extend magnetic relaxation and is typically carried out by dilution into a solvent or cocrystallization with an isostructural diamagnetic species. Herein, we report the first known example of extended magnetic relaxation through dilution into a paramagnetic medium. Using the canonical SMM [PPh₄]₂(Co(SPh)₄), dilutions into the isostructural paramagnets [PPh₄]₂(M(SPh)₄) (where M = Ni, Fe, and Mn) were made by cocrystallization. We show that across a range of concentrations, both Fe and Ni perform like the diamagnetic Zn congener, whereas the Mn dilution results in an accelerated relaxation. Dipolar interactions beetween spin centers are considered and we hypothesize that the observed relaxation enhancement can be attributed to low temperature magnetism of the paramagnetic diluents.