Antiferromagnetic coupling of the single-molecule magnet Mn12 to a ferromagnetic substrate

摘要

We investigate magnetic coupling between a monolayer of prototypesingle-molecule magnets Mn12 and a ferromagnetic Ni(111) substrate through S,using density-functional theory (DFT) and a DFT+U method. Our DFT and DFT+Ucalculations show that the Mn12 molecules favor antiferromagnetic coupling tothe Ni substrate, and that they possess magnetic moments deviated from themagnetic moments of isolated Mn12 molecules. We find that the magnetic easyaxis of the Mn12 on Ni (whole system) is dictated by that of the Ni substrate.The antiferromagnetic coupling is, dominantly, caused by superexchangeinteractions between the magnetic moments of the Mn and the Ni substrate viathe S, C, and O anions. Our findings can be observed from x-ray magneticcircular dichroism or scanning tunneling microscopy.