Bachelor topics 2021/2022

1) Study of molecular quantum bits by high-frequency electron paramagnetic resonance

In quantum computation the classic binary digit (bit) is replaced by a so-called quantum bit (qubit). Molecular spins are potential candidates for qubits depending on the lifetime (relaxation time) of their spin states. This property can be chemically engineered by changing organic ligands around the central metal atom. The goal of this work is the characterization of several molecular spin systems based on cobalt with different ligands using high-frequency electron paramagnetic resonance (HF-EPR) spectroscopy. This tool enables direct observation of spin transitions, and the simulation of EPR absorption spectra provides the intrinsic molecular magnetic parameters and relaxation times.

Supervisor: Dr. Vinicius Santana

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2) Microfabrication and characterization of thin films of ABC-stacked graphite and rotated graphene multilayers

Novel multilayered materials present remarkable physical properties, with exciting prospects of applications in new technologies. This project proposes the isolation and characterization of carbon-based materials with different stacking and orientations, like ABC-stacked graphite, a less stable polytype of graphite that is thought to support magnetic and superconducting phases, and rotated bilayer graphene, which is superconductive at given angles. Anyone can join this project, the only requirement is enthusiasm to learn and explore new things. All other necessary skills will be obtained during the project. It is an excellent opportunity to get training in state-of-the-art methods, such as AFM, STM, Raman spectroscopy, ARPES, and mechanical exfoliation, available at the facilities of CEITEC NANO. Candidates will work with experienced scientists of our research group “Magneto-Optical THz Spectroscopy -- MOTES” in a stimulating and supportive environment.

Supervisor: MSc. Jorge Navarro & Dr. Miroslav Bartoš

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3) Testing and optimization of the FTIR magneto-spectroscopic setup

Fourier Transform Infrared (FTIR) spectroscopy in high magnetic fields is an important method in characterizing various materials such as Single-Molecule Magnets (SMMs), promising molecular species for future data storage. This method allows studying Electron Paramagnetic Resonance (EPR) phenomenon in SMMs with very large zero-field splitting (ZFS), mainly based on transition metal complexes or lanthanides, in which conventional EPR systems do not provide experimental access to the magnetic resonance transitions. Besides, it presents an ideal experimental technique that can investigate the band structure and electronic properties of novel 2D materials such as graphene. The method of FTIR spectroscopy in high magnetic fields is mediated by compact FTIR magneto-spectroscopic setup built at CEITEC BUT, on which a variety of magneto-optical measurements will be performed after its testing and optimization.

Supervisor: Ing. Jana Dubnická Midlíková

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4) Driver of scanning coil for rapid scan EPR experiments

Rapid scan EPR is a method which works on rapid change of the magnetic field through resonance, to initiate interaction of microwave radiation with a paramagnetic sample. This change of magnetic field is in orders of 1 kT/s, while amplitude is relatively small in orders of 10 mT. Aim of this topic is to design and construct diver for a scanning coil based on principles of transconductance amplifier, in order to use linear scans of magnetic field.

Supervisor: Ing. Matúš Šedivý

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5) Software module for data acquisition in frequency scan experiments on HFEPR spectrometer

In EPR spectroscopy, a detected microwave signal of interest is often at same level or bellow as noise of a microwave detector. To improve signal to noise ratio, a modulation of signal before detection and demodulation after detection is done by device called Lock-in amplifier. However, this approach limits speed of experiments which are based on frequency scans. Therefore, such scans must be longer than period of modulation signal, by several orders. Alternative approach to increase signal to noise ratio an averaging of detected signal that is acquired by a high-speed digitizer. Aim of this project is to improve current software solution for HFEPR spectrometer. This will allow to compare two different approaches of improving signal to noise ratio, with respect to time efficiency.

Supervisor: Ing. Matúš Šedivý

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6) Development of a system for the calibration of temperature sensors in 1.8 – 320 K range

The in-house calibration of cryogenic temperature sensors can save about 2/3 of its price. This project is devoted to the development of a system that can perform a simultaneous calibration of up to 4 sensors in the range of 1.8 – 320 K. The student will design and assemble the insert probe, and also create software for collecting and processing of the sensors’ data (in Matlab, Python or Labview).

Supervisor: Dr. Oleksii Laguta

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