Advanced materials The study of preparation conditions of soft magnetic composites on their magnetic properties. Supervisor: Study form: Annotation:

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1 Advanced materials The study of preparation conditions of soft magnetic composites on their magnetic properties. Supervisor: Prof. RNDr. Peter Kollár, DrSc. Annotation: The study is oriented on investigation of preparation conditions of soft magnetic composites consisting of particles based on ferromagnetic metals and alloys with inorganic or organic insulators prepared by uniaxial compaction. The most important factors influenced the properties of resulting material are the chemical composition of ferromagnetic component, the fraction of non-ferromagnetic component, temperature, atmosphere and duration of compaction. The aim is optimization of compaction process of soft magnetic materials with required magnetic properties at middle-frequency ac magnetic fields. Literature: 1. R. M. Bozorth Ferromagnetism, third edition (IEEE Press, Piscataway, NJ), H. Shokrollahi, K. Janghorban J. Mater. Proc. Technol. 189 (2007) 1 The study of magnetic and structural properties nanoparticles for biomedical application Supervisor: Assoc. Prof. RNDr. Adriana Zeleňáková, PhD. Co-supervisor: Assoc. Prof. RNDr. Vladimír Zeleňák, PhD. Annotation: Since magnetic particles have unique features, the development of a variety of medical applications has been possible. The most unique feature of magnetic particles is their reaction to a magnetic force, and this feature has been utilized in applications such as drug targeting and as contrast agents for magnetic resonance imaging (MRI). Recently, magnetic nanoparticles have attracted attention because of their potential as heating mediators for cancer therapy (hyperthermia). The aim of PhD work is optimization of synthesis strategy for preparation of magnetic nanoparticles for magnetic hyperthermia and as advanced drug delivery system. References: 1. S. Gubin, Magnetic Nanoparticles, 2009 Wiley-VCH Verlag GmbH & Co. KGaA 2. J. L. Dorman, D. Fiorani, Magnetic Properties of Fine Particles, 1992 North Holland 3. R. Hillzinger, W. Rodewald, Magnetic Materials, 2012 Wiley-VCH Verlag GmbH & Co. KGa.

2 Multifunctional composite nanoparticles for biomedical applications Supervisor: Assoc. Prof. RNDr. Vladimír Zeleňák, PhD. Co-supervisor: Assoc. Prof. RNDr. Adriana Zeleňáková, PhD. Annotation: The thesis will deal with the preparation and detailed study of core-shell nanoparticles composed of magnetic core (e.g. Fe3O4) and outer nanoporous silica shell. The designed nanoparticles can be used as magnetic resonance imaging agents and/or as targeted drug delivery vehicles, thus making them as candidates for simultaneous cancer diagnosis and therapy. The thesisi will involve synthesis of multifunctional nanoparticles by sol-gel techniques, their detailed structural analysis (SEM, TEM, XRD, N 2 adsorption), the investigation of their magnetic properties (SQUID magnetometry) and investigation of their use in adsorption and delivery of the cytostatics. Influence of anisotropy induced by thermal treatment on structural and magnetic properties of rapidly quenched soft magnetic materials Supervisor: prof. RNDr. Rastislav Varga, DrSc. Co-supervisor: Assoc. Prof. RNDr. Zuzana Vargová, PhD. Annotation: The aim of the work is to study the influence of anisotropy induced by thermal treatment (under mechanical stress, magnetic field, etc.) on structural and magnetic properties of rapidly quenched materials in the shape of ribbons and wires. Formation of highly porous micro- and nanostructures by magnetron sputtering for application in energy conversion technologies. Supervisor: Mgr. Vladimír Komanický Ph.D. Co-supervisor: Mgr. Tomáš Samuely Ph.D. Annotation: The sphere of use of catalysts is incredibly broad practically all chemical reactions in industry are catalytic. Nowadays the problem of developing clean energy is particularly acute, and the hydrogen economy is one of its leading sectors [1]. Catalysts play an important role in development of hydrogen economy [2], in particular, they are able to improve the efficiency of water electrolysis, photodecomposition of water, methane decomposition when obtaining hydrogen and to enhance the performance of fuel cells when converting the chemical bound energy of hydrogen and oxygen directly into electrical energy. Hydrogen and oxygen evolution reactions as well as oxygen reduction reaction are catalytic reactions, which play a key role in the efficiency of obtaining hydrogen and in generation of electrical energy [3]. That is why the main goal of dissertation thesis will be directed to the obtaining of catalysts for the above-mentioned reactions. The obtaining of porous structures of gold and platinum during PhD research will be conducted by a single-step magnetron sputtering.

3 Literature: 1. Crabtree, G. W., Dresselhaus, M. S., & Buchanan, M. V. (2004). The hydrogen economy. Physics Today, 57(12), Armor, J. N. (2005). Catalysis and the hydrogen economy. Catalysis letters, 101(3-4), Mallouk, T. E. (2013). Water electrolysis: Divide and conquer. Nature chemistry, 5(5), The structure determination of binary metallic glasses by synchrotron based scattering and spectroscopic techniques and image techniques at XFEL. Supervisor: Prof. RNDr. Pavol Sovák, CSc. Co-supervisors: RNDr. Štefan Michalik, PhD., Ing. Karel Saksl, DrSc. Annotation: Binary metallic systems are in general considered to be incapable to form bulk amorphous alloys due to not satisfying the confusion principle. However, current experimental works have identified several binary systems, for example Cu-Hf and Ni-Ta, suitable for producing bulk metallic glasses in the form of rods and strips. To understand the origin of such an unexpected excellent glass forming ability in these systems, structure investigations are essential. The thesis will deal with the preparation of binary (Fe, Ni, Cu)-(Hf,Ta,W)-based metallic glasses in the form of ribbons and rods by melt-spinning technique and the copper mould casting method. The glassy structure of the as-prepared alloys will be investigated by synchrotron based scattering and spectroscopic techniques, namely high-energy X-ray diffraction (HEXRD), anomalous X-ray diffraction (AXRD) and X-ray absorption spectroscopy (XAS). The special interest will be devoted to the AXRD technique to explore its feasibility by using large 2D detectors. Structure of the samples also will be checked by TEM and by MID beamline at XFEL in Hamburg. References 1. N.A. Mauro, A.J. Vogt et al., Anomalous structural evolution and liquid fragility signatures in Cu-Zr and Cu-Hf liquids and glasses, Acta Materialia 61 (2013) Y. Wang, Q. Wang, J. Zhao and Ch. Dong, Ni-Ta binary bulk metallic glasses, Scripta Materialia 63 (2010) Development and research on thermoelectric materials Supervisor: Ing. Karel Saksl, DrSc. - Institute of Materials Research Slovak Academy of Sciences Annotation: Thermoelectrics exhibit so called Seebeck effect which allows converting thermal energy directly into electricity. It is projected that the world market of thermoelectric devices and harvesters will grow five times, to over $950 million by Thesis of the dissertation work will describe novel progress in thermoelectrics and their preparation. Applicant will prepare alloys with highest Seebeck efect, characterise thermoelectric and structural properties of selected alloys. Part of the thesis will focus on development and characterisation of brand new alloys targeted to thermoelectric applications. Highly ionized plasma sputtering of carbide, boride and nitride coatings. Supervisor: doc. RNDr. František Lofaj, DrSc. - Institute of Materials Research Slovak Academy of Sciences

4 Annotation: Magnetron sputtering is oriented toward technologies with high ionization degree of the sputtered material which provides better control of the deposition process as well as better coating properties. The most famous ionized PVD is the High Power Impuslse Magnetron Sputtering (HiPIMS) and the relatively new techology High Target Utilization Sputtering (HiTUS) also belongs among these methods. High degree of ionization is achieved in the case of HiPIMS by very short duty cycle impulses with extremely high power density whereas in HiTUS by the power at an independent plasma source. The work should focus on the optimization of the depozition parameters of hard multicomponent carbide, boride and nitride coatings from the viewpont of the control of their elastic and plastic properties by means of determination of dependencie among the depozition parameters, plasma characteristics, coating structures and their mechanical and tribological properties. The work will be performed on the ipvd systems Cryofox Discovery (Polyteknik, Denmark) and HiTUS C500 (PQL, UK) in combination with the electron microscopy observations (SEM, TEM) and measurements of mechanical properties. HiPIMS Discovery HiTUS C500 nanoindentation in W-C coating Quantitative characterization of plasma deposition and carbide and boride based ceramic coatings by optical and electron spectroscopy methods. Supervisor: doc. RNDr. František Lofaj, DrSc. - Institute of Materials Research Slovak Academy of Sciences Annotation: The advanced ceramic coatings for higly demanding applications( e.g. ultrahigh temperature thermal shields for reentry vehicles, protective barriers for ultrahigh speed cutting) consist of high melting point and heavy (Zr, Hf, Ru, W..) metallic elements strongly bonded with light elements (boron, nitrogen, oxygen, carbon with hydrogen) which result in difficulties in quantitative analysis when using conventional chemical methods. Usually, a combination of several analytical methods is necessary to obtain quantitative characterization of both light and heavy elements at the same time in the resulting compounds. However, the control of the coating composition requires also the control of the plasma composition during the deposition. Thus, the in situ methods of plasma composition should be combined with the methods applied to the coatings to determine the relationships controlling their chemistry, structure and properties. The work should employ an in-situ optical emission spectroscopy for the plasma control with the exsitu glow discharge optical emission spectrocopy (GDOES), Raman spectroscopy as well as energy and wavelength disperse electron spectroscopy (and potentially also X-ray Photoelectron Spectroscopy (XPS) and Secondary Ion Mass Spectrocopy (SIMS)) methods on the carbide and boride based coatings for quantification of their chemistry to establish the correlations between the plasma characteristics and their structure and properties. The plasma study will be performed on the existing ipvd systems using OES system (Avantes, The Netherlands)and Raman microscope (XploRa, Horiba, France), GDOES (GD2, Horiba, France) as well as on the EDS and WDS

5 (Oxford, UK) attached to the scanning electron microscopes. The introduction of new XPS and SIMS facilities is also anticipated. Ramanovský mikroskop GDOES FIB-SEM s EDS Mapping of the mechanical and tribological properties of ceramic ipvd layers at micro- and nano-level. Supervisor: doc. RNDr. František Lofaj, DrSc. - Institute of Materials Research Slovak Academy of Sciences Annotation: The development of MEMS is bound to the development of the technologies for their preparation and characterization of the mechanical properties, reliability and lifetimwe at nanolevel. The development of this field resulted from the development of corresponding imaging and testing methods at nano-level. The most famous methods involve atomic force microscopy (AFM), nanoindentation incl. in-situ nanoindentation in an scanning electron microscope and nanolitography. AFM combines imaging capabilities in various modes with the modes related to the measurement of physical, mechanical, tribological and other properties down to atomic level. The aim of the work should be the mapping of the mechanical and tribological properties of different types of ipvd coatings at micro- and nano-level by means of a combination of different AFM modes in an AFM (Dimension Icon, USA) with the nanoindenter (G200, Agilent, USA), eventually, by an in-situ nanoindentation in a scanning electron microscope. AFM - Dimension Icon nanoindentor Agilent G200

6 Development of one-dimensional composite fibrillar materials for energetic application Supervisor: RNDr. Magdaléna Strečková, PhD. - Institute of Materials Research Slovak Academy of Sciences Annotation: Nano and mickro fibers represent materials with unique properties and incomparable advantages such are: extremely high specific surface area to volume ratio, regular pore distribution and interconnectivity, low density, high mechanical strength, possible surface modification what allows diverse surface chemistry. Among various chemical or physical synthetic approaches, electrospinning appears to be the most straightforward and versatile technique for generating 1D nanostructures. The dissertation work will be focused on preparation the carbonaceous fibers via needle-less electrospinning method doped with metals or phosphides of metals for a new generation of the materials for the effective production of hydrogen and energy saving. These materials will address a wide variety of energy applications, including mass applications in large scale electronics, electric vehicles or for stationary electrical energy storage. 1. S. Cavaliere, Electrospinning for advanced energy and environmental applications 2015, CRC Press, ISBN X. Wang, T. Lin, Needleless electrospinning of nanofibers: Technology and Applications 2013, Pan Stanford, ISBN Development of new soft magnetic composites based on ferromagnetic materials and hybrid coatings. Supervisor: RNDr. Magdaléna Strečková, PhD. - Institute of Materials Research Slovak Academy of Sciences Annotation: Soft magnetic composite materials produced by compactization of ferromagnetic powder particles isolated from each other with dielectric component represent a separate class of materials which combine excellent magnetic properties of metals and their alloys (high values of magnetic saturation and low coercitive force in magnetic reversal field) and ferrite, because of its dielectric nature having almost zero eddy current losses in the magnetic reversal of AC magnetic fields with regards to an overall loss. However, to create such a material with the point of view of future users is tied to find a compromise between the magnetic properties as well as acceptable mechanical properties. A clear advantage is to prepare dielectrics coatings with high specific electric resistance (polymer), but with the possibility of magnetic activity (ferrite). The main objective of the thesis is to design, prepare and characterize the potential dielectric material as an adequate coating on ferromagnetic microparticles with the highest mechanical and thermal resistance towards the temperature at which the final material will be used. 1. H. Shokrollahi,, K. Janghorban, Soft magnetic composite materials (SMCs), Journal of Materials Processing Technology, 189 (2007), Bas J.A., Calero J.A., Dougan M.J., Sintered soft magnetic materials. Properties and applications, J Magn Magn Mater (2003) Thermodynamic description and modeling of phase diagrams of systems with boron. Supervisor: RNDr. Viera Homolová, PhD. - Institute of Materials Research Slovak Academy of Sciences

7 Annotation: Scope of the work will be modelling of phase diagrams of selected ternary systems with boron by using suitable description of their Gibbs energy. Calphad method, combining theoretical approach and results of experimental measurements, will be used for the modeling. Output of the work will be thermodynamic database allowing various thermodynamic calculations. The work will be focused on the systems with boron because of widely using of borides in atomic power and chemical industry, next forming of boride coatings on varies alloys and metals and last but not least as subsystems of steels for energy industry and for production abrasive and corrosion-resistant components. Structure and properties of magnetoelectric materials Supervisor: RNDr. Vladimír Kovaľ, PhD. - Institute of Materials Research Slovak Academy of Sciences Annotation: The study is focused on multiferroic ceramics that exhibit simultaneously magnetic and ferroelectric order at and above room temperature. The main objectives include preparation and chatacterization of the crystal structure, microstructure and physical (electrical, magnetic) properties of magnetoelectrics. An AC impedance spectroscopy will be adopted and modified in order to evaluate the effect of chemical composition on dielectric response of the investigated materials. Correlations of magnetic and mechanical properties of selected composite materials Supervisor: Ing. Radovan Bureš, CSc. - Institute of Materials Research Slovak Academy of Sciences Annotation: The goal is study of change of magnetic, elastic and mechanical properties of soft magnetic composite materials in dependence on compaction parameters. Investigated materials will be prepared on the basis of powder ferromagnetic metals and alloys. Ferromagnetic particles will be coated by ceramic, polymeric or hybrid electro-insulation coating layer. Shaping and compaction will be realised using conventional methods as well as progressive microwave sintering and spark plasma sintering methods. The compaction parameter influence on the structure and properties of prepared composite. The influencing level of electric, magnetic, elastic and mechanical properties could be significantly different. Thesis will be focused on identification and quantification of correlations among compaction parameters, structure and properties as well as correlations among the materials characteristics of prepared composites.