V(TCNE)x: the electronic structure of an enigmatic, organic-based room temperature magnet revealed
(English)Manuscript (preprint) (Other academic)
We have prepared and characterized thin films of V(TCNE)x in ultra-high vacuum using a novel film growth technique based on in-situ chemical vapor deposition of tetracyanoethylene, TCNE, and bis-benzene vanadium, V(C6H6)2. The in-situ preparation method enabled, for the first time, experimental analysis of the electronic structure. X-ray magnetic circular dichroism (XMCD) measurements recorded at the V L2,3-edge confirmed room temperature magnetic ordering. A combination of conventional photoelectron spectroscopy (PES) and resonant photoemission (RPE) measured at the x-ray absorption edges (V L3-edge, C K-edge, N K-edge) shows that the highest occupied electronic state is V(3d)-derived. Nearly complete quenching of the V(3d) orbital angular momentum is observed from the low value of the integrated XMCD signal, indicating a strong ligand field. The rearrangements of the TCNE" related valance electronic states observed in PED and near edge x-ray absorption fine structure (NEXAFS) spectra, in combination with the evidence of V(3d) and TCNE" π (π*) orbital overlap contained in RPE spectra, also point to strong, covalent type bonding.
Engineering and Technology
IdentifiersURN: urn:nbn:se:liu:diva-85558OAI: oai:DiVA.org:liu-85558DiVA: diva2:571629