Abstract
We investigated the magnetic properties and spin interface of tetrafluorotetracyanoquinodimethane (F4-TCNQ)-tailored nickel (Cu(100)/Ni) surface which display enhanced magnetic ordering at lower critical thickness of Ni film. Surface magnetic anisotropy performed by the magneto-optical Kerr effect (MOKE) displays magnetic hardening upon F4-TCNQ adsorption. The magnetic domains inspected by photoelectron-emission microscope (PEEM) measurements also exhibits improved magnetic ordering with larger domain sizes and less domain boundary. To elucidate the origin of enhanced magnetic ordering after molecular tailoring, surface-sensitive and element specific X-ray Magnetic Circular Dichroism (XMCD) were employed. The XMCD reveals the orbital and spin moment of in-plane Ni is significantly increased, while that keep almost unaltered at out-of-plane. Through the strong superexchange coupling at in-plane, the nonmagnetic F4-TCNQ is spin polarized. Our results suggest the enhanced magnetic ordering of such organic-ferromagnetic interface is an effective spin filtering for constructing high efficient organic spintronics.