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PhD topics for academic year 2021/2022

Department of Inorganic Chemistry

Chemistry and Technology of Materials

Faculty of Chemical Technology

Elucidating the origin of magnetoelectric coupling in Fe4M2O9 phases

Sedmidubský David, prof. Dr. Ing. ( sed...@vscht.cz)
Multiferroic materials exhibiting at least two ferroic orders such as ferroelectricity and ferromagnetism are the focus of researchers attention. The magneto-electric coupling is very appealing for applications in devices, such as memories, where the magnetic information has to be controlled by an electric field. The thesis work will focus on the synthesis and the study of the structural/magnetic/dielectric/ ferroelectric properties of Fe4M2O9 mono- and poly-crystals. As these Fe2+ containing oxides exist only for M = Nb and Ta, the thermodynamic stability of these phases will be calculated in connection with their magneto-elastic coupling.
University of Normandy
Faculty of Chemical Technology

Impact of the magnetism on the thermoelectric properties of oxides and sulfides

Jankovský Ondřej, Doc. Ing. Ph.D. ( Ond...@vscht.cz)
Thermopower can be very sensitive to spins and magnetism, and its enhancement has already been observed in oxides, as exemplified in NaxCoO2 or in misfit cobaltites. Recently, the impact of magnetism has been evidenced in ferromagnetic and metallic CoS2 with an extra contribution to thermopower measured in the. In the insulating thiospinel CuCrTiS4, the transport properties are actually very similar to magnetoresistant oxides, with variable range hopping transport associated to a large negative magnetoresistance and magnetothermopower. The aim of this project is to investigate the influence of magnetism on the thermoelectric properties of these sulfides presenting different ground states, to tune and optimize this enhancement of thermopower. A detailed investigation of the thermal properties will also be realized.
University of Normandy
Faculty of Chemical Technology

Structural, Magnetic and Thermoelectric Properties of TM in ZnO / ZnS: Effects of Nano-sizing

Nádherný Ladislav, Ing. Ph.D. ( Lad...@vscht.cz)
In the past ten years, the interest in zinc oxide research in the field of magnetic semiconductors has significantly increased. According to the Zener model, manganese-doped ZnO is one of the systems in which ferromagnetic behavior could be achieved even at room temperature. Since the solubility of magnetic Mn in bulk ZnO is very limited, new approaches to prepare thin films and nanoparticles with higher dopant concentration are used. The aim of this doctoral dissertation is to prepare nanopowders based on ZnO with the highest concentration of Mn as possible. Prepared powders will be characterized by means of XRD, TEM, DSC, DLS, PPMS, and the nanosizing effect on the Mn solubility in ZnO or ZnS will be described.
University of Normandy

Department of Metals and Corrosion Engineering

Chemistry and Technology of Materials

Faculty of Chemical Technology

High-entropy alloys prepared by powder metallurgy techniques

Průša Filip, Ing. Ph.D. ( Fil...@vscht.cz)
Cabibbo Marcello, Prof. ( m.c...@staff.univpm.it)
Since the year 2004, the materials research gained a new way of focusing on special alloys made initially of five elements with equiatomic compositions. The newly discovered group of materials has been since then known as high-entropy alloys (HEA) due to a high entropy of mixing which allows creating predominantly solid solutions instead of intermetallic phases. These materials are known to be exhibiting a variety of excellent properties that often combine high strengths while maintaining good ductility, good corrosion resistance and others.
The work will aim at the description of the microstructure-related properties of high-entropy alloys prepared by powder metallurgy techniques combining mechanical alloying and compaction via spark plasma sintering.
Università Politecnica delle Marche
Faculty of Chemical Technology

Mechanism of the formation of intermetallics in mechanical alloying

Novák Pavel, doc. Ing. Ph.D. ( pan...@vscht.cz)
Cabibbo Marcello, Prof. ( m.c...@staff.univpm.it)
Mechanical alloying is a popular technology for the preparation of powders of alloys or intermediary compounds (e.g. intermetallics, carbides or borides) by high energy mechanical milling. The high popularity of the method is given by the fact that it usually leads to nanostructured materials and that even non-miscible elements can create solid solutions during mechanical alloying. Even though the result is known and there are many descriptions available, the mechanism of the formation of intermetallics in this process is not fully understood yet. The reasons are probably in a large variety of possible process parameters and by impossibility to measure the temperature inside the powder in the milling jar. This work proposes following concept: indirect determination of the dependence of the peak powder temperature on milling conditions (rpm, ball-to-powder ratio, ball size) by the use of thermally decomposing salts, comparison of phase composition of the mechanically alloyed powder with the reference powder mixture exposed in the furnace to the detected peak temperature and observation of the time development of the microstructure and phase composition by XRD and electron microscopy (SEM, TEM). The mechanism will be observed on several different systems containing brittle and ductile powders (e.g. Ti-Al, Ti-Si, Ti-Al-Si) and the general conclusion regarding the mechanical alloying mechanism will be formulated.
Università Politecnica delle Marche

Department of Polymers

Chemistry and Technology of Materials

Faculty of Chemical Technology

Preparation of olefin block copolymers

Merna Jan, doc. Ing. Ph.D. ( m...@vscht.cz)
Zinck Phillipe, Prof. Ph.D. ( phi...@univ-lille.fr)
The thesis will be focused on the preparation of block copolymers based on olefin and diene monomers by coordination copolymerizations. The focus will be on copolymers with blocks of different properties, e.g. hard and soft blocks. Principles of coordination chain transfer polymerization and chain-shuttling polymerization will be applied. Introduction of polar functional groups will also be of interest. The work will include organometallic synthesis of catalysts, polymerization experiments in presence of various transfer agents and full characterization of obtained polymers.
École Nationale Supérieure de Chimie de Lille, France
Updated: 29.11.2019 12:30, Author: Jan Kříž

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