On surface spin tuning in single molecule magnets
Final Report Abstract
The project focuses on the investigation of the structural, electronic and magnetic properties of individual single molecule magnets (SMMs) at surfaces as well as on the controllable manipulation of their fundamental properties. In the frame of this project, we implemented a unique combination of deposition methods and investigation techniques aiming to reveal detailed insight in electronic states and spin properties of well-defined adsorbed single molecular magnets on functional substrates as well as to tune their electronic properties to controllably modify their magnetic behavior. By using electrospray deposition (ESD), we established in situ preparation of Fe4 H SMMs on various substrates, including, graphene/Ir(111), Pb(111), and Au(111), which serves as an ideal starting point for addressing individual molecules. Molecular orbitals were investigated using scanning tunneling spectroscopy (STS). The intramolecular exchange interaction is determined by inelastic spin excitations and shows intact molecular magnetism. The magnetic anisotropy is investigated using X-ray absorption spectroscopy (XAS) and depends on the respective substrate. For the first time, successful chemical doping by attaching individual Li atoms to such large, polynuclear compounds has been demonstrated. The influence of doping on the electronic and magnetic properties is investigated in detail by STM and XAS measurements. Further, we were able to demonstrate the successful in situ deposition of Ln-based dimetallofullerenes of the structure Ln2 @C80 (R) with Ln = Dy and Tb, which is complemented by detailed characterization by STM and STS measurements. The mapping of molecular orbitals showed good agreement with ab initio calculations and allowed the assignment of relevant molecular orbitals. XAS experiments reveal largely intact molecular magnetism with a closure of the hysteresis curve above 2 K, effectively doubling the previously measured magnetic blocking temperature in surface-adsorbed SMMs.
Publications
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Electrospray Deposition and Magnetic Properties of Prototypical Molecular Magnets. Quantum Materials Research.
F. Paschke, Ph. Erler, J. Dreiser, L. Gragnaniello & M. Fonin
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Exceptionally High Blocking Temperature of 17 K in a Surface‐Supported Molecular Magnet. Advanced Materials, 33(40).
Paschke, Fabian; Birk, Tobias; Enenkel, Vivien; Liu, Fupin; Romankov, Vladyslav; Dreiser, Jan; Popov, Alexey A. & Fonin, Mikhail
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Imaging the Single‐Electron Ln–Ln Bonding Orbital in a Dimetallofullerene Molecular Magnet. Small, 18(3).
Paschke, Fabian; Birk, Tobias; Avdoshenko, Stanislav M.; Liu, Fupin; Popov, Alexey A. & Fonin, Mikhail
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Cooperative and selective redox doping switches single-molecule magnetism. Science Advances, 11(21).
Paschke, Fabian; Briganti, Matteo; Enenkel, Vivien; Birk, Tobias; Dreiser, Jan; Schmitt, Peter; Winter, Rainer F.; Totti, Federico & Fonin, Mikhail
