Spin properties of single-molecule magnet of double-decker Tb(III)-phthalocyanine (TbPc2) on ferromagnetic Co film characterized by spin polarized STM (SP-STM)

We demonstrate a direct visualization of the magnetic hysteresis of a single-molecule magnet bis(phthalocyaninato)terbium(III) (TbPc2) adsorbed on the Co islands, which covers a submonolayer region of an Au(111) surface by utilizing the spin-polarized scanning tunneling microscope (SP-STM) and monitoring the magnetotunneling resistance. We found that the TbPc2 molecule is spin polarized and attached to the ferromagnetic Co islands. The result of the SP-STM measurements showed that the spin of TbPc2 is antiferromagnetically coupled to the magnetization of the Co island. In addition, we found an opening in the hysteresis curve even with the frozen magnetization of the Co island, unlike that with near-zero remanence typically reported for the bulk crystal and the nonmagnetic substrate.