Exchange bias induced by molecular spinterface

Abstract

Molecular spins as individual are promising quantum states for coming computation technology. The “on surface” configuration of molecules in proximity to a magnetic film allows control over the orientations of molecular spins and interfacial coupling between them. The stacking of planar molecular spins could favor antiferromagnetic interlayer coupling and lead to pinning of the magnetic underlayer via exchange bias, extensively utilized in magnetic devices. Here, we show tunable molecular exchange bias and its asymmetrical magnetotransport features by varying composition of metalloporphyrin/ferromagnet bilayers. The systems exhibit a wide range of interfacial coupling (ferromagnetic or antiferromagnetic) and exchange bias. Transport measurements of the bilayers reveal the molecular exchange bias effect on a fabricated device, representing asymmetric behaviors on anisotropic and angle-dependent magnetoresistance. Theoretical calculations demonstrate the orientation of spins and interfacial magnetic coupling, and further understanding to exchange bias. A study of interfacial coupling in molecule/ferromagnet systems and its impact on magnetic and magnetotransport behaviors will extend functionalities of molecular spinterface for emerging information technology.