A5033063365- Glass properties and applications
- Luminescence Properties of Advanced Materials
- Electron Spin Resonance Studies
- Magnetism in coordination complexes
- Advanced NMR Techniques and Applications
- Random lasers and scattering media
- Lanthanide and Transition Metal Complexes
- X-ray Diffraction in Crystallography
- Magneto-Optical Properties and Applications
- Crystallization and Solubility Studies
- Topological Materials and Phenomena
- Graphene research and applications
- Solid-state spectroscopy and crystallography
- Solid State Laser Technologies
- Quantum and electron transport phenomena
- Silicon Carbide Semiconductor Technologies
- Quantum optics and atomic interactions
- Photorefractive and Nonlinear Optics
- Advancements in Battery Materials
- Semiconductor materials and devices
- Photonic Crystal and Fiber Optics
- Spectroscopy and Laser Applications
- Semiconductor materials and interfaces
- Chemical and Physical Properties of Materials
- Optical and Acousto-Optic Technologies
Brno University of Technology
2019-2025
Central European Institute of Technology
2019-2024
University of Stuttgart
2018
Stuttgart Observatory
2018
Center for Integrated Quantum Science and Technology
2018
Centre National de la Recherche Scientifique
2015-2017
Laboratoire de Physique des Lasers, Atomes et Molécules
2017
Université de Lille
2015-2016
Electron paramagnetic resonance (EPR) is a powerful technique to investigate the electronic and magnetic properties of wide range materials. We present first combined terahertz (THz) field frequency domain electron (HFEPR/FDMR) spectrometer designed structure molecular systems, thin films solid state materials in very broad 85-1100 GHz. In this paper, we show high resolution frequency-field (Zeeman) maps (170-380 GHz by 0-15 T) recorded on two single-molecule magnets, [Mn2(saltmen)2(ReO4)2]...
The ${F}^{+}$ center consisting of an electron trapped at oxygen vacancy (${V}_{\mathrm{O}}$) was investigated in deficient ${\mathrm{Y}}_{3}{\mathrm{Al}}_{5}{\mathrm{O}}_{12}$ (YAG) garnet crystals by paramagnetic resonance (EPR) techniques. measurements were performed the wide temperature interval 5--450 K and frequency range 9.4--350 GHz using both conventional continuous-wave pulse EPR experiments. Pulse electron-nuclear double applied to resolve hyperfine interaction with surrounding...
Abstract Graphene has been proven to be an excellent material for high-frequency electromagnetic radiation detection. Here, we are reporting the graphene quantum dots (GQDs) devices designed as multi-parallel arrays of (200 nm in diameter) between source and drain electrodes. These state-of-the-art provide a novel concept tuning total device area impedance while maintaining superior performance. The GQDs have fabricated on silicon oxide substrate analyzed their transport properties. array...
Electron paramagnetic resonance (EPR) of Mn4+ ions and optical absorption spectra are studied in the lithium–sodium tetragermanate LiNaGe4O9 crystal range a ferroelectric phase transition. Anisotropy EPR evidences that substituted for Ge hosts within oxygen octahedra. Double splitting lines below transition temperature (TC = 114 K) indicates lowering symmetry (C2 → C1) sites. The components g factor hyperfine interaction tensor A, axial D, rhombic E field parameters have been determined from...
We report on the investigation of Bismuth-doped pure silica glass without other co-dopant by tech- nique magnetic circular dichroism (MCD), which allows direct probing ground state optical centres. Taking into account results conventional spectroscopy, we show that observed MCD bands belong to centre responsible for red photoluminescence in this material. Measurements temperature and field dependences indicate effect is caused even-electron system. This, however, opposes widespread opinion...
A structurally new heptadentate derivative of a 15-membered pyridine-based macrocycle containing two benzimidazol-2-yl-methyl N-pendant arms (L = 3,12-bis((1H-benzimidazol-2-yl)methyl)-6,9-dioxa-3,12,18-triazabicyclo[12.3.1]octadeca-1(18),14,16-triene) was synthesized and its complexes with the general formula [M(L)](ClO4)2·1.5CH3NO2 (M MnII (1), FeII (2), CoII (3) NiII (4)) were thoroughly investigated. X-ray crystal structures confirmed that all are seven-coordinate axially compressed...
Semiconductor devices based on $15R$ silicon carbide (SiC) show improved properties compared to other polytypes. Here, we report the investigation of nitrogen-doped SiC monocrystals with $({N}_{\mathrm{D}}--{N}_{\mathrm{A}})\ensuremath{\sim}5\ifmmode\times\else\texttimes\fi{}{10}^{18}\phantom{\rule{0.16em}{0ex}}\mathrm{c}{\mathrm{m}}^{\ensuremath{-}3}$ using multifrequency electron paramagnetic resonance (EPR) and electrically detected magnetic (EDMR) spectroscopic methods in microwave (MW)...
Electron spin resonance (ESR) is a powerful spectroscopic technique used to investigate samples with unpaired electrons in broad range of scientific fields. High-frequency ESR (HF-ESR) spectrometers operating at sub-THz frequencies are mostly custom-made non-standard solutions. This article presents set six different exchangeable sample holders fast-loading flange for spectrometer high magnetic fields up 16 T and temperature ranges 4–400 K. Here, we report on the concept, design,...
The development of pulse electron spin resonance (ESR) spectroscopy at microwave frequencies above 100 GHz is rather challenging and expensive due to the low output power modern high-frequency solid state electronics. However, there a number scientific problems that require relaxation measurements THz frequencies. rapid scan ESR an alternative technique does not high still provides information on times. method takes advantage fast sweeps excitation frequency over line. When sweep reaches...
Strontium titanate ($\mathrm{SrTi}{\mathrm{O}}_{3}$) is the most known material from family of quantum paraelectrics. Thanks to its extremely ``soft'' lattice, functionality can be easily tuned by applying both external stimuli (pressure, strain, electric field) and through doping or isotope exchange. In this paper, we present results a detailed study two $\mathrm{M}{\mathrm{n}}^{2+}$ centers in Mn-doped $\mathrm{SrTi}{\mathrm{O}}_{3}$ single crystals using continuous wave pulsed electron...
This work focuses on unraveling electron paramagnetic resonance (EPR) and electrically detected magnetic (EDMR) properties of <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:mi>n</a:mi></a:math>-type <b:math xmlns:b="http://www.w3.org/1998/Math/MathML"><b:mrow><b:mn>6</b:mn><b:mi>H</b:mi></b:mrow></b:math> silicon carbide (SiC) single crystals with high concentrations uncompensated nitrogen (N) donors, which is essential for fundamental understanding spin-related phenomena,...
Bismuth-doped-silica-based optical fibers as a laser gain medium covers the spectral regions inaccessible to conventional rare-earth-doped fibers. Unfortunately, nature of luminescent centers in these is not well understood, which complicates development efficient devices. In this Letter magnetic-field-induced circular polarization near-infrared (NIR) photoluminescence (PL) Bi-doped pure silica glass was studied range 660–1600 nm, covering three excited state levels. The results variable...
Electrically detected magnetic resonance (EDMR) is an effective spectroscopic method utilized for characterizing semiconductive solid-state materials. High spin sensitivity and the capability to explore spin-dependent transport mechanisms, which are crucial development of semiconductor devices, defining it from other methods based on resonance. frequency high field EDMR implementation was motivated by necessity obtain access more precise, high-resolution data in order enhance method's...
The pulse electron paramagnetic resonance (EPR) is widely used in different branches of material and life sciences, including promising applications quantum information processing sensing. Here, we study the effect high polarizability KTaO3 SrTiO3 paraelectrics on local electric magnetic field components microwaves (MW) at Fe3+ Mn2+ ions. measurements are performed with a commercial EPR spectrometer using dielectric split-ring resonators. It found that power MW pulses coherent spin...
This paper presents results of a detailed magneto-optical spectroscopy study bismuth-doped aluminosilicate glass. At least three distinct optical centres are shown to coexist in the glass: bismuth ion clusters, Bi+ ions and defects glass structure, with energy transfer between last two species. Analysis magnetic circular dichroism polarisation luminescence as functions field temperature indicates that all have an even number electrons (holes). Experimental evidence is presented both 'red'...
Abstract For over the past two decades it has been believed that intense orange-red photoluminescence in Bismuth-doped materials originates from Bi $$^{2+}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mrow/> <mml:mrow> <mml:mn>2</mml:mn> <mml:mo>+</mml:mo> </mml:mrow> </mml:msup> </mml:math> ions. Based on results magnetic circular polarization experiments, we demonstrate this hypothesis fails for silica glasses. Our findings contradict generally accepted...
Unusual temperature dependence of the anti-Stokes photoluminescence (ASPL) at 734 nm was found in Ga/Bi co-doped sol-gel silica glass. While range 450-873 K, behavior ASPL is completely determined by thermal population excited state levels, its intensity continuously increasing with decreasing 77-430 K. By measuring pump power 300 we show that latter can be described via two-step intracenter excitation process and subsequent relaxation. Based on measurements spectra near infrared band (at...