Molecular spintronics attempts both to improve the properties of current electronic devicesand develop completely new devices by combining the advantages of molecular electronicsand spintronics into one research eld. Investigating and evaluating the properties ofmolecular magnets and to eventually employ them in devices is a major goal of molecularspintronics. Two dierent kinds of molecular magnets are promising candidates for devicedevelopment: Single-molecule magnets (SMMs) and hybrid-molecular magnets. Both areideal building blocks for spintronic devices, such as spin-transistors and spin-valves. Howeverthe fabrication of devices requires the deposition on surfaces. Due to the interaction betweenmolecules and surfaces being highly complex, only a fundamental understanding of thesephenomena will eventually lead to the succesful application of molecular magnets in devices.To improve the understanding of the molecule-surface interaction both approacheshave been investigated experimentally in this dissertation. Since surfaces are prone tocontamination, these experiments were conducted in ultra-high vacuum. To gain moreinsight in such systems and to understand the adsorption phenomena, their structural,electronic and magnetic properties were studied on a microscopic scale with scanningtunneling microscopy (STM) and spectroscopy (STS).The interaction between SMMs and surfaces was exemplarily studied by depositing fNi4gon Au(111). fNi4g is a recently synthesized SMM where a cubane fNi II4 (3Cl)4g core isresponsible for the magnetic properties [1]. The magnetic core is protected by organic ligandsexhibiting a thioether surface functionalization. Since thioether functionalized ligands hadbeen widely neglected in earlier experiments, the deposition of fNi4g on Au(111) fromsolution and the resulting adsorption phenomena were studied by XPS and STM. Bothmethods revealed strong evidence for a ligand detachment during adsorption. The magneticcore however might be still structurally intact as indicated by XPS. Attempts to desorbthe detached ligands and to subsequently image the magnetic core with STM by in-situpost-annealing were unsuccessful. Instead the post-annealing lead to the decomposition ofthe magnetic core and to a most likely sulfur induced reconstruction of the Au(111) surface.As a results of this study new strategies have been proposed to avoid the ligand detachmentin future experiments.In a complementary approach the interaction between molecules and surfaces is exploitedfor the formation of hybrid-molecular magnets. Here, comparatively stable non-magneticmolecules are deposited on magnetic surfaces. The interaction leads to a magnetic moleculesurfacehybrid, or "hybrid-molecular magnet".This approach requires a magnetic substrate. For this task the well known Fe/W(110)system was chosen and charaterized by spin-polarized STM (SP-STM). The fabrication ofsuitable magnetic tips for SP-STM is a well known challenge due to its poor predictabilityand reproducibilty. The characterization of tips was performed by SP-STM measurementson the Fe/W(110) system and reveals that Cr-coated tips exhibit the required out-of-planemagnetization direction for the following experiments on hybrid-molecular magnet systems.Furthermore an eective spin polarization of up to 12.4% for the whole tip-sample tunneljunction was found.
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