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High frequency electron spin resonance spectroscopy
Hrubý, Jakub ; Perfetti, Mauro (oponent) ; ShangDa, Jiang (oponent) ; Neugebauer, Petr (vedoucí práce)
Electron spin resonance (ESR) is a non-invasive magnetic-resonance-based spectroscopic technique. It is used in many scientific fields such as biology, chemistry, and physics to investigate systems with unpaired electrons. This doctoral thesis deals with high-frequency electron spin resonance (HF-ESR) spectroscopy and its use on paramagnetic coordination compounds. The first part outlines theoretical basics with literature research in this field and shows the HF-ESR applications. Afterwards, methods used to study systems of interest are presented. Herein, the complementary spectroscopic methods (XPS, RS, UV-VIS, AFM, SEM) are described, and the design of a newly built high-vacuum (HV) sublimation chamber was developed for the preparation of thin films of coordination compounds on surfaces. The next part deals with results obtained by HF-ESR on molecular quantum bits [Cu(dbm)2], single-molecule magnets [CoX2(dppf)], [Co(4MeO-L)2Cl2], and vision of graphene-based bolometers for detection of this class of compounds is outlined. The results are further discussed, and their implications are summarised in conclusions. Finally, references and the author's outputs make up the final chapters of this work.
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Depozice molekulárních magnetů na „2D“ materiály
Vavrečková, Šárka ; Musálek, Tomáš (oponent) ; Hrubý, Jakub (vedoucí práce)
Tato bakalářská práce se zabývá depozicí jedmolekulárních magnetů na 2D materiály a studiem jejich chování na površích. Teoretická část pojednává o jednomolekulárních magnetech, způsobech jejich depozice a vybraných 2D materiálech – grafenu a sulfidu molybdeničitém. Dále jsou popsány fyzikální principy zvolených charakterizačních metod (mikroskopie atomárních sil, Ramanova spektroskopie, rentgenová fotoelektronová spektroskopie a elektronová paramagnetická rezonance). V experimentální části byla provedena exfoliace grafitu a sulfidu molybdeničitého a následně depozice vybraného jednomolekulárního magnetu jak z roztoku tak pomocí termální sublimace. Výsledné vícevrstevnaté vzorky byly posléze charakterizovány pomocí zmíněných metod a na závěr byly diskutovány výsledky.
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Hybrid materials based on magnetically bistable molecular compounds
Vavrečková, Šárka ; Herchel, Radovan (oponent) ; Nemec, Ivan (vedoucí práce)
This thesis deals with the deposition of single-molecule magnets on graphene. The theoretical part is devoted to single-molecule magnets, selected deposition methods suitable for depositing single-molecule magnets on two-dimensional substrates, and graphene. Furthermore, the physical principles of the chosen characterization methods (atomic force microscopy, scanning electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy and electron paramagnetic resonance) are discussed. In the experimental part, the deposition of six cobalt single-molecule magnets was carried out by thermal sublimation. Two of them were also deposited from solution by drop-casting to verify their high stability. The samples were then analyzed using the methods mentioned above, and the results were discussed. The successful depositions led to the identification of stable single-molecule magnets with promising magnetic properties.
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Preparation and Characterization of Graphene Based Hybrid Materials
Hrubý, Jakub ; Novák, Jiří (oponent) ; Neugebauer, Petr (vedoucí práce)
Graphene with metal complexes could provide novel approaches in graphene-based hybrid materials and molecular magnetism. Both topics are highly innovative as such, however, there is a little research into possibilities of mixing them. Samples were prepared by a liquid-phase sonication of graphite which resulted in the exfoliation of graphene. Subsequently, various metal complexes were deposited onto a graphene-covered substrate by modiied Langmuir–Schaefer method. An essential step was to determine the material’s properties. Consequently, properties of new hybrid materials were characterised by high frequency electron paramagnetic resonance (HFEPR), scanning electron microscopy (SEM), Raman spectroscopy and four-point probe resistance measurements. Herein, the results conirmed our presumption that it is possible to mix exfoliated graphene with potential molecular magnets in order to gain novel magnetic and electronic properties which could be possibly utilised in the next generation of detectors and electronics.
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Hybrid materials based on magnetically bistable molecular compounds
Vavrečková, Šárka ; Herchel, Radovan (oponent) ; Nemec, Ivan (vedoucí práce)
This thesis deals with the deposition of single-molecule magnets on graphene. The theoretical part is devoted to single-molecule magnets, selected deposition methods suitable for depositing single-molecule magnets on two-dimensional substrates, and graphene. Furthermore, the physical principles of the chosen characterization methods (atomic force microscopy, scanning electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy and electron paramagnetic resonance) are discussed. In the experimental part, the deposition of six cobalt single-molecule magnets was carried out by thermal sublimation. Two of them were also deposited from solution by drop-casting to verify their high stability. The samples were then analyzed using the methods mentioned above, and the results were discussed. The successful depositions led to the identification of stable single-molecule magnets with promising magnetic properties.
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High frequency electron spin resonance spectroscopy
Hrubý, Jakub ; Perfetti, Mauro (oponent) ; ShangDa, Jiang (oponent) ; Neugebauer, Petr (vedoucí práce)
Electron spin resonance (ESR) is a non-invasive magnetic-resonance-based spectroscopic technique. It is used in many scientific fields such as biology, chemistry, and physics to investigate systems with unpaired electrons. This doctoral thesis deals with high-frequency electron spin resonance (HF-ESR) spectroscopy and its use on paramagnetic coordination compounds. The first part outlines theoretical basics with literature research in this field and shows the HF-ESR applications. Afterwards, methods used to study systems of interest are presented. Herein, the complementary spectroscopic methods (XPS, RS, UV-VIS, AFM, SEM) are described, and the design of a newly built high-vacuum (HV) sublimation chamber was developed for the preparation of thin films of coordination compounds on surfaces. The next part deals with results obtained by HF-ESR on molecular quantum bits [Cu(dbm)2], single-molecule magnets [CoX2(dppf)], [Co(4MeO-L)2Cl2], and vision of graphene-based bolometers for detection of this class of compounds is outlined. The results are further discussed, and their implications are summarised in conclusions. Finally, references and the author's outputs make up the final chapters of this work.
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Depozice molekulárních magnetů na „2D“ materiály
Vavrečková, Šárka ; Musálek, Tomáš (oponent) ; Hrubý, Jakub (vedoucí práce)
Tato bakalářská práce se zabývá depozicí jedmolekulárních magnetů na 2D materiály a studiem jejich chování na površích. Teoretická část pojednává o jednomolekulárních magnetech, způsobech jejich depozice a vybraných 2D materiálech – grafenu a sulfidu molybdeničitém. Dále jsou popsány fyzikální principy zvolených charakterizačních metod (mikroskopie atomárních sil, Ramanova spektroskopie, rentgenová fotoelektronová spektroskopie a elektronová paramagnetická rezonance). V experimentální části byla provedena exfoliace grafitu a sulfidu molybdeničitého a následně depozice vybraného jednomolekulárního magnetu jak z roztoku tak pomocí termální sublimace. Výsledné vícevrstevnaté vzorky byly posléze charakterizovány pomocí zmíněných metod a na závěr byly diskutovány výsledky.
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Preparation and Characterization of Graphene Based Hybrid Materials
Hrubý, Jakub ; Novák, Jiří (oponent) ; Neugebauer, Petr (vedoucí práce)
Graphene with metal complexes could provide novel approaches in graphene-based hybrid materials and molecular magnetism. Both topics are highly innovative as such, however, there is a little research into possibilities of mixing them. Samples were prepared by a liquid-phase sonication of graphite which resulted in the exfoliation of graphene. Subsequently, various metal complexes were deposited onto a graphene-covered substrate by modiied Langmuir–Schaefer method. An essential step was to determine the material’s properties. Consequently, properties of new hybrid materials were characterised by high frequency electron paramagnetic resonance (HFEPR), scanning electron microscopy (SEM), Raman spectroscopy and four-point probe resistance measurements. Herein, the results conirmed our presumption that it is possible to mix exfoliated graphene with potential molecular magnets in order to gain novel magnetic and electronic properties which could be possibly utilised in the next generation of detectors and electronics.
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