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Design of the far-infrared spectrometer coupling to a superconductive magnet and magneto-optical measurements in the far-infrared region
Dubnická Midlíková, Jana ; Slageren, Joris van (oponent) ; Neugebauer, Petr (vedoucí práce)
The thesis deals with the development of the far-infrared (FIR) spectroscopy in the high magnetic field. The combination of the FIR spectroscopy and high magnetic field is a very important tool in the characterization of materials such as Single-Molecule Magnets (SMMs). It also presents an ideal experimental technique that can probe and elucidate properties of novel 2D materials. The FIR spectroscopy in the magnetic field also allows studying Electron Paramagnetic Resonance (EPR) of SMMs with very large zero-field splitting, mainly based on transition metal complexes or lanthanides, in which commonly used EPR systems do not provide experimental access to the magnetic resonance transitions. In the thesis, two setups of the FIR spectrometers coupled to the superconductive magnets are described in detail. The first described setup, located at the University of Stuttgart, is already assembled and its performance is discussed. The magneto-optical measurements of SMMs performed on this setup are presented. The second magneto-optical setup draws on the experiences gained in the first setup and is designed for CEITEC.
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Development of Fourier Transform InfraRed Spectroscopy in High Magnetic Fields
Dubnická Midlíková, Jana ; Marsik, Přemysl (oponent) ; Schnegg, Alexander (oponent) ; Neugebauer, Petr (vedoucí práce)
Fourier-transform infrared (FTIR) spectroscopy in high magnetic fields, concisely FTIR magneto-spectroscopy, is a powerful spectroscopic technique used to investigate many important effects in materials, e.g., electron paramagnetic resonance, cyclotron resonance, and transitions between Landau levels. Despite their enormous potential in solid-state physics, infrared magneto-spectrometers are still relatively rare and custom-made since such systems generally require complex infrastructure. This doctoral thesis describes in detail the design and implementation of a versatile FTIR magneto-spectroscopic setup operating in the range of 50 – 10 000 cm-1, high magnetic field up to 16 T and temperatures between 2 – 320 K located at the Central European Institute of Technology of Brno University of Technology. This setup allows us to perform a variety of magneto-optical measurements spanning the range from THz/far-infrared (FIR) to near-infrared (NIR). It consists of a commercial FTIR spectrometer coupled to a 16 T cryogen-free superconductive magnet by the custom-designed optical coupling and transmission probes designed for experiments with multiple detectors and samples in Faraday geometry. The novelty of the setup lies in the usage of a cryogen-free superconducting magnet. We have optimized and tested the performance of the FTIR magneto-spectroscopic setup for various configurations and determined a workable setup range. The functionality of the FTIR magneto-spectroscopic setup was demonstrated by the magneto-optical measurements of the zero-field splitting in cobalt(II)-based single ion magnet in the FIR region, indirect inter-band transitions between Landau levels (LLs) in germanium in the NIR region, and inter-band transitions between LLs in graphene in the FIR region. Moreover, we measured the I-V characteristics of graphene bolometer devices.
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Design of the far-infrared spectrometer coupling to a superconductive magnet and magneto-optical measurements in the far-infrared region
Dubnická Midlíková, Jana ; Slageren, Joris van (oponent) ; Neugebauer, Petr (vedoucí práce)
The thesis deals with the development of the far-infrared (FIR) spectroscopy in the high magnetic field. The combination of the FIR spectroscopy and high magnetic field is a very important tool in the characterization of materials such as Single-Molecule Magnets (SMMs). It also presents an ideal experimental technique that can probe and elucidate properties of novel 2D materials. The FIR spectroscopy in the magnetic field also allows studying Electron Paramagnetic Resonance (EPR) of SMMs with very large zero-field splitting, mainly based on transition metal complexes or lanthanides, in which commonly used EPR systems do not provide experimental access to the magnetic resonance transitions. In the thesis, two setups of the FIR spectrometers coupled to the superconductive magnets are described in detail. The first described setup, located at the University of Stuttgart, is already assembled and its performance is discussed. The magneto-optical measurements of SMMs performed on this setup are presented. The second magneto-optical setup draws on the experiences gained in the first setup and is designed for CEITEC.
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