Fischer, Arne Stephen (2015)
Crystalline and amorphous cluster-assembled nanomaterials, synthesized with a novel cluster deposition system.
Technische Universität Darmstadt
Ph.D. Thesis, Primary publication
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Item Type: | Ph.D. Thesis | ||||
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Type of entry: | Primary publication | ||||
Title: | Crystalline and amorphous cluster-assembled nanomaterials, synthesized with a novel cluster deposition system | ||||
Language: | English | ||||
Referees: | Hahn, Prof. Dr. Horst ; Kappes, Prof. Dr, Manfred | ||||
Date: | 2015 | ||||
Place of Publication: | Darmstadt | ||||
Date of oral examination: | 5 May 2015 | ||||
Abstract: | Clusters are generally defined as aggregates of three up to several million atoms or molecules. In recent years, it has been shown, that especially small clusters in the size-range of a few nanometers can exhibit unique, size-dependent properties (e.g. magnetic, electronic), differing them from their bulk material counterparts. Therefore, synthesizing materials based on size-selected clusters may pave the way to new types of materials with tailorable properties. In order to be able to synthesize any kind of cluster-composed material with a high degree of control over the various material characteristics, a cluster ion beam deposition system was designed, ion-optically simulated, and constructed. Thereby, the focus was to develop a versatile system, that offers as much control as possible over the various deposition parameters. Experiments on two cluster/matrix nanocomposites, namely iron/silver and iron/chromium, as well as a purely cluster-composed material based on amorphous iron-scandium alloy clusters, were conducted with the newly developed deposition system. The experiments on iron/silver revealed, that the cluster ion beam deposition system allows to synthesize cluster-composed materials with, amongst other features, an outstanding degree of control in terms of deposited amounts of clusters, and homogeneity of the synthesized samples. The focus of the experiments on iron/chromium was to thoroughly study the magnetic characteristics of the ferromagnetic(iron)/ antiferromatic (chromium) samples. The obtained results yielded insights into the relation between the various magnetic characteristics, for example the exchange bias effect, and the sample parameters, i.e. the size of the embedded clusters and the cluster volume fractions in the samples. Finally, experiments are presented, where a material purely composed of amorphous Fe-Sc alloy clusters was characterized. The obtained results indicate, that by systematic variation of the deposition parameters, a new amorphous structure with altered properties compared to conventional amorphous material, typically prepared by rapid quenching, was synthesized. |
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Uncontrolled Keywords: | Cluster, cluster deposition, nanoglasses, cluster/matrix nanocomposites, exchange bias | ||||
URN: | urn:nbn:de:tuda-tuprints-46314 | ||||
Classification DDC: | 500 Science and mathematics > 500 Science 500 Science and mathematics > 530 Physics 600 Technology, medicine, applied sciences > 620 Engineering and machine engineering |
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Divisions: | 11 Department of Materials and Earth Sciences 11 Department of Materials and Earth Sciences > Material Science 11 Department of Materials and Earth Sciences > Material Science > Joint Research Laboratory Nanomaterials |
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Date Deposited: | 08 Oct 2015 08:14 | ||||
Last Modified: | 09 Jul 2020 00:58 | ||||
URI: | https://tuprints.ulb.tu-darmstadt.de/id/eprint/4631 | ||||
PPN: | 365314145 | ||||
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