Magnetism of TbPc ₂ on ferromagnetic iron oxide surface

Abstract Thin inorganic films, such as metal oxides, are frequently employed as functional materials for decoupling or optimization of the interaction between molecular magnetic layers and metallic surfaces. In the case of single-molecule magnet (SMM) deposits, an effective decoupling layer can reduce the hybridization with the metallic substrate, which would otherwise suppress their intrinsic magnetic bistability. In this work, we investigate the potential of an ultra-thin Fe oxide layer as a substrate for the Tb(III) bis-phthalocyaninato (TbPc ₂ ) SMM in technological platforms. A multi-technique approach was employed to evaluate the integrity of a TbPc ₂ sub-monolayer (ML) deposit and to determine the molecular adsorption geometry at the surface. Furthermore, large-scale facilities experiments were performed, and x-ray magnetic circular dichroism was used to probe the magnetic properties of the TbPc ₂ sub-ML. The central finding is that while the magnetic moments and electronic configuration of the molecule are preserved, the characteristic slow magnetic relaxation is suppressed. This highlights the critical role of substrate phonon stiffness and tunnel barrier thickness in stabilizing the SMM behaviour.