Roughness-induced magnetic decoupling at organic-inorganic interface

We have investigated structural, electronic and magnetic properties of H${}_2$Pc on Fe${}_2$N/Fe using low-energy electron diffraction and soft x-ray absorption spectroscopy/x-ray magnetic circular dichroism. Element specific magnetization curves reveal that the magnetic coupling with H${}_2$Pc enhances the perpendicular magnetic anisotropy of Fe${}_2$N/Fe at the H${}_2$Pc coverage of 1 molecular layer. However, adding two and three molecular layers of H${}_2$Pc reverts the shape of magnetization curve back to the initial state before H${}_2$Pc deposition. We successfully link appearance and disappearance of the magnetic coupling at the H${}_2$Pc-Fe${}_2$N/Fe interface with the change of hybridization strength at N sites accompanied by the increase in the H${}_2$Pc coverage.