A TbPc2 sub-monolayer deposit on a titanium dioxide ultrathin film: magnetic, morphological, and chemical insights

Abstract

Thin inorganic films (i.e., metal oxides) are often used as decoupling layers to optimize the interactions between the magnetic layers of molecules and metallic surfaces. For deposits of single-molecule magnets (SMMs), a decoupling layer can minimise the hybridization of the metallic substrate that is responsible for the quenching of their typical magnetic bistability. Here, we explored the potential of a single layer of titania to be used as a decoupling layer, which could represent an interesting playground for widespread use in many technological applications. We used a TiO₂ monolayer with a lepidocrocite-like structure grown on a Ag(100) substrate for the deposition of the terbium(III) bis-phthalocyaninato (TbPc₂) complex. A multi-technique approach employing X-ray photoelectron spectroscopy and scanning tunnelling microscopy was used to examine the integrity of a TbPc₂ sub-monolayer deposit and to study the molecular adsorption configuration on the TiO₂ film. Furthermore, X-ray magnetic circular dichroism was used to investigate the magnetic properties of the TbPc₂ sub-monolayer, revealing that the TiO₂ film successfully preserves the molecular spin character. X-ray-based magnetic measurements showed that the quantum tunnelling of the magnetization characterizing a bulk of molecules is still present and that the present titania film displays a decoupling effect of comparable efficiency to that of a graphene layer.