A5049870241- Ferroelectric and Piezoelectric Materials
- Microwave Dielectric Ceramics Synthesis
- Advanced ceramic materials synthesis
- Multiferroics and related materials
- Intermetallics and Advanced Alloy Properties
- Additive Manufacturing and 3D Printing Technologies
- Nuclear materials and radiation effects
- Additive Manufacturing Materials and Processes
- Magnetic and transport properties of perovskites and related materials
- Advanced Condensed Matter Physics
- Advanced materials and composites
- High-pressure geophysics and materials
- Magnetic properties of thin films
- Solid-state spectroscopy and crystallography
- Material Science and Thermodynamics
- High-Temperature Coating Behaviors
- Fiber-reinforced polymer composites
- Nanomaterials for catalytic reactions
- Copper Interconnects and Reliability
- Metal and Thin Film Mechanics
- Luminescence Properties of Advanced Materials
- Thermal and Kinetic Analysis
- Pigment Synthesis and Properties
- TiO2 Photocatalysis and Solar Cells
- Supercapacitor Materials and Fabrication
Central European Institute of Technology
2013-2024
Brno University of Technology
2013-2024
Central European Institute of Technology
2023
X-ray diffraction, dynamical mechanical analysis and infrared reflectivity studies revealed an antiferrodistortive phase transition in EuTiO3 ceramics. Near 300K the perovskite structure changes from cubic Pm-3m to tetragonal I4/mcm due antiphase tilting of oxygen octahedra along c axis (a0a0c- Glazer notation). The is analogous SrTiO3. However, some ceramics as well single crystals show different spectra bringing evidence a crystal structure. In such samples electron diffraction...
This work demonstrates the carbonization of centrifugally spun polyacrylonitrile (PAN) fibers. Initially, optimal centrifugal spinning conditions for producing homogeneous PAN fibers were identified. Second, process continued by stabilization and to ensure a pure carbonaceous fiber material eliminating all non-carbonaceous matter. The stabilized at 240 °C in air heating rate 1 °C/min, then carbonized between 600 1200 argon 5 °C/min. After carbonization, characterized using scanning electron...
The phase purity and the lattice dynamics in bulk EuTiO${}_{3}$ were investigated both microscopically, using x-ray neutron diffraction, ${}^{151}$Eu-M\"ossbauer spectroscopy, ${}^{151}$Eu nuclear inelastic scattering, macroscopically calorimetry, resonant ultrasound magnetometry. Furthermore, our investigations corroborated by $ab\phantom{\rule{0.28em}{0ex}}\mathit{initio}$ theoretical studies. perovskite symmetry, $Pm\overline{3}m$, is unstable at $M$- $R$-points of Brillouin zone....
Sintering of pure cordierite 2MgO:2Al2O3:5SiO2, and with the addition 5 mass % TeO2 was studied. Green bodies were prepared from powder mixtures mechanically activated in a high-energy planetary mill, shaped by uniaxial (20 MPa) cold isostatic pressing (1000 MPa). The pressure-less sintering these specimens performed at 1350°C for 1 h. High relative density over 95% theoretical value obtained through solid-state reaction 40 min, first time reported literature. Phase composition...
Cordierite-based ceramic materials are attracting much interest for their various applications in industry, manufacturing multilayer circuit boards, catalytic converters, filters, thermal insulation, kiln furniture, components of portable electronic devices, etc. In order to reduce production costs and modify cordierite-based materials, mechanical activation can be used. this study, microstructural electrical properties mechanically activated MgO-Al2O3-SiO2 system have been analyzed. The...
Using time-differential perturbed angular correlation of γ rays, we investigated the electric-field gradient polycrystalline EuTiO3 and Eu2Ti2O7, with 181Hf(181Ta) as a probe, following different thermal treatments. The measurements were performed at ISOLDE-CERN 80 keV implantation Bonn Radioisotope Separator. experimental results indicated successful induction phases in recovery process 1273 1373 K. These observations combined ab initio calculations X-ray diffraction measurements. A...
Molybdenum is a refractory metal regarded as promising basis for producing high-temperature components. However, the potential of manufacturing molybdenum-based structures by direct ink writing (DIW) has not been explored. In this study, three-dimensional porous molybdenum (Mo) and molybdenum-silicon (Mo-Si) composite lattices were fabricated using DIW with non-milled milled powders. The effects Mo powder morphology (resulting from milling) chemical composition (alloying 3 10 wt.% Si) on...
In this article, the advantages of combined sintering in comparison with conventional one, mechanically activated magnesium titanate ceramic were investigated. The stoichiometric mixtures MgO and TiO2 mechano-chemically for 0, 10, 40, 80 160 minutes by ball milling then isostatically pressed (CIP) to form green bodies. Conventional was realized heating up 1400 oC hold 30 air atmosphere. Resulting samples closed porosity post-sintered pressure assisted technique Hot Isostatic Pressing (HIP)...
In the antiferromagnetic phase of $\mathrm{Eu}\mathrm{Ti}{\mathrm{O}}_{3}$ ceramics, a seemingly anisotropic magnetodielectric effect (up to 2.5%) was observed via low-frequency dielectric permittivity measured in external magnetic field below 1.9 T. We explain theoretically by taking into account demagnetizing which effectively reduces internal flux density 0.6 T when is applied perpendicular plane disk-shaped sample. This finding also confirmed experimentally magnetization measurements....
Magnetic resonance spectra of EuTiO3 in both bulk and thin film form were taken at temperatures from 3-350 K microwave frequencies 9.2-9.8 34 GHz. In the paramagnetic phase, magnetic are determined by dipole exchange interactions between Eu2+ spins. film, a large contribution arises demagnetization field. From detailed analysis linewidth its temperature dependence, parameters spin-spin determined: frequency is 10.5 GHz estimated critical exponent spin correlation length ≈0.4. samples,...
Materials with high strength-to-weight ratio exhibiting excellent static tensile strength, fatigue and creep resistance are of great interest in a wide range applications, such as aerospace or power generation. For the majority demanding structures components, Al Ti alloys (in particular Ti6Al4V) most widely used. Recently, cold spraying is being recognized an efficient additive manufacturing process (cold spray manufacturing, CSAM). However, CSAM deposition Ti6Al4V challenging task,...
Based on the earlier published theory (Nature Mat. 18, 223-228 (2019)), a comprehensive experimental investigation of multiferroic quantum critical behavior (Eu,Ba,Sr)TiO$_3$ polycrystalline and single crystal samples was performed. Presence displacive ferroelectric criticality is revealed through non-classical ($T^2$) temperature scaling inverse dielectric susceptibility up to 60 K. With increasing hydrostatic pressure, this gradually suppressed. Inverse magnetic follows classical...
Based on the earlier published theory [A. Narayan, Nat. Mater. 18, 223 (2019)], a comprehensive experimental investigation of multiferroic quantum critical behavior (Eu,Ba,Sr)${\mathrm{TiO}}_{3}$ polycrystalline and single-crystal samples was performed. The presence displacive ferroelectric criticality is revealed through nonclassical (${T}^{2}$) temperature scaling inverse dielectric susceptibility up to 60 K. With increasing hydrostatic pressure, this gradually suppressed. Inverse magnetic...
This report demonstrates the development of carbon fibers (CFs) decorated with TiO 2 nanoparticles (NPs) as an efficient photocatalyst for photocatalytic degradation methylene blue (MB) a model dye. Carbon were produced by carbonization polyacrylonitrile fibers, previously centrifugal spinning. Subsequently, CFs NPs (CFs@TiO ) tailored soaking protocol using aqueous TiCl 4 solution different concentrations (0.025, 0.05, 0.1, and 0.2 M). SEM analyses revealed that in smooth, conformal,...
EuTiO3 and Eu0.5Ba0.5TiO3 ceramics were synthesized using mechanochemical activation of oxide precursors then calcined. The uniaxially as well isostatically pressed samples sintered in different kinds reducing atmospheres, namely Ar + (7–10)%H2, respectively, 99.99%H2 the case pressureless sintering or vacuum (enriched by CO vapors) pressure-assisted spark plasma (SPS). prepared SPS contained pyrochlore phase second phase. In contrast with SPS, pure, although thermodynamics calculations...
Materials with high strength-to-weight ratio exhibiting excellent static tensile strength, fatigue and creep resistance are of great interest in a wide range applications, such as aerospace or power generation. For the majority demanding structures components, Al Ti alloys (in particular Ti6Al4V) most widely used. Recently, cold spraying is being recognized an efficient additive manufacturing process (cold spray manufacturing, CSAM). However, CSAM deposition Ti6Al4V challenging task,...