Coupling TbPc2 single molecule magnets to antiferromagnetic FeMn layers

Coupling of single molecule magnets to magnetically ordered (ferromagnetic or antiferromagnetic) layers is a novel research field that has potential applications in molecular-scale spintronic devices. In this study we explore the possibility to magnetically couple TbPc2 molecules to FeMn layers deposited on a Cu (100) substrate. Using X-ray magnetic circular dichroism we demonstrate that, following field cooling, the out-of-plane Tb magnetization loop is vertically shifted and, furthermore, the Tb and Fe magnetization are antiferromagnetically coupled. Additionally, it is found that the Fe magnetization loop is vertically shifted and that this vertical shift depends on the elemental composition of the FeMn layer. The hysteretic behavior of the Tb magnetization together with the horizontal shift of the Tb loop are consistent with the hypothesis that a fraction of the TbPc2 molecules are coupled to the uncompensated Fe spins through a ligand-mediated superexchange mechanism.