Enhanced anisotropy and study of magnetization reversal in Co/C60 bilayer thin film

TL;DR

This study investigates the magnetic interface properties of Co/C60 bilayer thin films, revealing enhanced anisotropy and altered magnetization reversal due to orbital hybridization at the interface, with detailed neutron reflectivity measurements.

Contribution

It provides new insights into the magnetic interface (spinterface) in Co/C60 bilayers and demonstrates enhanced anisotropy linked to orbital hybridization effects.

Findings

Spinterface thickness is approximately 2 nm with a magnetic moment of 0.8 μB per cage.

Magnetization reversal behavior is modified in bilayers compared to single Co layers.

Anisotropy in bilayers is roughly doubled due to interfacial effects.

Abstract

The interface between organic semiconductor [OSC]/ferromagnetic [FM] material can exhibit ferromagnetism due to their orbital hybridization. Charge/spin transfer may occur from FM to OSC layer leading to the formation of `spinterface' i.e. the interface exhibiting a finite magnetic moment. In this work, the magnetic properties of Co/C$_{60}$ bilayer thin film have been studied to probe the interface between Co and C$_{60}$ layer. Polarized neutron reflectivity [PNR] measurement indicates that the thickness and moment of the spinterface are $\sim$ 2 $\pm$ 0.18 nm and 0.8 $\pm$ 0.2 $\mu_B$/cage, respectively. The comparison of the magnetization reversal between the Co/C$_{60}$ bilayer and the parent single layer Co thin film reveals that spinterface modifies the domain microstructure. Further, the anisotropy of the bilayer system shows a significant enhancement ($\sim$ two times) in comparison to its single layer counterpart which is probably due to an additional interfacial anisotropy arising from the orbital hybridization at the Co/C$_{60}$ interface.