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Light propagation in magnetic materials
Wagenknecht, David ; Ostatnický, Tomáš (advisor) ; Veis, Martin (referee)
Transparent magnetic materials, among the others semiconductors, have recently come to the focus of interest in both basic and applied research because they have great potential in optical applications and they can be used in optical spectroscopy to investigate fundamental physical phenomena. The theoretical calculations introduce that these materials have some extraordinary properties like asymmetric reflectance when light impact the sample from the opposite angles. In this bachelor thesis, transfer matrix formalism is derived based on Maxwell equations, taking into account special form of effective permittivity. The reflection coefficient for one layer demonstrates, that the asymmetric reflectance appears for transversal- magnetic polarization of light and transversal magnetization in the studied material. The derived formulae are used to calculate the difference in reflectivities for the waves impacting the structure from opposite angles. Ga1−xMnxAs with different concentrations of manganese is assumed to be the essential transparent magnetic layer in the sample. 1
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Magnetooptical spectroscopy of La2/3Sr1/3MnO3 ultrathin films
Zahradník, Martin ; Veis, Martin (advisor) ; Postava, Kamil (referee)
High quality La2/3Sr1/3MnO3 (LSMO) ultrathin layers are of interest for applications in magnetic sensors and spintronic devices due to colossal magnetoresistance of these materials. LSMO films studied in this thesis were grown by pulsed laser deposition on SrTiO3 substrates. The deposition at low oxygen pressures with the use of a beam homogenizer leads to the high quality LSMO films. The film thickness ranges from 5,0 to 103,9 nm. Magnetooptical (MO) spectrometer based on azimuth modulation was used and spectra of MO Kerr effect in polar and longitudinal configuration were obtained. All the spectra display features typical for LSMO films, including the thinnest 5 nm thick film. MO Kerr effect observed in this film reflects high magnetic ordering even at such low thickness. All the spectra manifest high quality of the LSMO films prepared with the use of the beam homogenizer.
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Employment Services for Former Substance Users in the Czech Republic in Comparison with Similar Services in Scotland and Austria
Veis, Štěpán ; Kocianová, Renata (advisor) ; Kopecký, Martin (referee)
The diploma thesis "Employment Services for Former Substance Users in the Czech Republic in Comparison with Similar Services in Scotland and Austria" discusses the problem of employment of people that used illegal drugs for some time in their lives and now abstain. To get a job and keep it is fundamental for them to be able to prosper in newly started life. Former substance users are characterized with respect to their position in the labour market and the need of social reintegration. Their employability in the Czech labour market is given from the point of view of the clients and workers of the treatment facilities, and from the point of view of potential employers. The possibilities of employment services offered to former substance users are then shown by three projects, i.e. Czech Work and Social Agency of SANANIM, o. s., Scottish Addiction Workers' Training Programme, carried out by Scottish Drugs Forum, and Austrian social firm Fix und Fertig, a branch of Verein Wiener Sozialprojekte. The projects are compared as to their approaches to the problem of employability, basic parameters that employment services offered to the former substance users should take into account are defined, and finally, the possibilities of development of these services in the Czech Republic are outlined.
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Advanced simulations of photonic structures by FDTD method
Vozda, Vojtěch ; Veis, Martin (advisor)
Finite-Difference Time-Domain method (FDTD) is based on numerical solution of Maxwell's equations, nowadays widely used for simulating optical response of photonic structures. This paper provides brief introduction to the FDTD method and several important extensions which make the basic code much more versatile. In order to broaden analysis of photonic structures, transfer matrix method (TMM) is also involved. The code is firstly tested using simple model structures which optical response might be compared with different numerical or even analytical approaches. Debugged code is used to improve photonic crystals for enhanced sensitivity of biosensing devices based on refractive index changes of sensed medium. Last but not the least, properties (sensitivity and Q-factor of resonant peak) of holey waveguide are investigated in one-, two- and three-dimensional simulation. It is shown here, that even this simple structure may compete with complex photonic crystals in the field of biosensors. Powered by TCPDF (www.tcpdf.org)
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Magneto-optical spectroscopy of perovskites thin films with colossal magnetoresistence
Veis, Martin
Najzev prace: Magneto-opticka spektroskopie tenkych vrstev perovskitu s kolosalm mag- netorezistenci Autor: Martin Veis Katedra (ustav): Fyzikalni ustav Univerzity Karlovy Vedouci diplomove prace: Prof. Ing.Stefan ViSnovsky, DrSc. e-mail vedouciho: visnov@karlov.mff.cuni.cz Abstrakt: Magnetoopticka spektra perovskitu s zelezitymi kationty v oblasti od 2 do 6 eV se vyznacuji bohatou strukturou a ostrymi liniemi. Jejich elektricky odpor je vysoky. To je zpusobeno existenci jedineho typu kationtu s peti elektrony na hladinach 3d, ktery se naleza v centru kyslikoveho oktaedru se shizenou symetrii. Nahrada zelezitych iontu ionty Mn s ruznou valenci mem radikalne elektricky odpor i krystalografickou symetrii a nutne musi nalezt odraz i v optickych vlastnostech. Ty nebyly zatim na tenkych vrstvach pfipraven}^ch pulzni laserovou depozici systematicky studovany. Diplomova prace je ve- novana magnetoopticke spektroskopii tenkych vrstev v oblasti 1 az 5 eV v zavislosti na tloust'ce v mezich od 20 do 60 nm s cilem pfispet novymi poznatky o elektronove struktufe techto vrstev. Klifiova slova: Kerruv magnetoopticky jev, Laz/sSri/sMnOs, Pulzni laserova depozice Title: Magneto - optical spectroscopy of perovskites thin films with colossal magnetore- sistence Author: Martin Veis Department: Institute of Physics, Charles...
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Problems of employment of ex-drug users
Veis, Štěpán ; Sycha, Martin (referee) ; Kocianová, Renata (advisor)
The presented bachelor thesis "Problems of Employment of Ex-Drug Users" describes possibilities of their entering the labour market and ways of support that are offered to them nowadays in the Czech Republic. The thesis is divided into seven thematic chapters that deal with present situation at the labour market with respect to the specific needs of ex-drug users, their characteristics, including a short outline of drug addiction treatment and their opportunities at the labour market as seen both by clients and staff members of therapeutic facilities and by potential employers in territory of the City of Prague. Finally, the thesis describes ways of seeking jobs the ex-drug users may make use of and summarizes legislative specifics of their employment. The closing chapter is devoted to the description of the "Work and Social Agency" project of SANANIM NGO from the point of view of the author's own practice there.
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Vectorial Kerr magnetometry
Flajšman, Lukáš ; Veis,, Martin (referee) ; Urbánek, Michal (advisor)
Increased complexity of novel magnetic materials in the last decade has placed high demands on the manufacturing process as well as on the characterization. One of the possibilities for characterization of magnetic samples is to exploit the magneto-optical effects. The presented work uses the magneto-optical Kerr effect as a major characterization technique to probe the magnetic properties of samples. We have developed a mathematical model describing the effect of the magnetization on the polarized light and present an apparatus capable of measuring the response given by the light-matter interaction. The experimental results show the performance of the apparatus on the various magnetic systems including meta-stable iron layers, Stoner-Wohlfarth particles and magnetic vortices. The scanning vectorial Kerr magnetometer allowed us to probe the vector of magnetization with diffraction limited resolution below 500 nm.
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Analýza webových stránek vybraných leteckých společností v ČR
Veis, Richard ; Toman, Prokop (advisor) ; Pösinger, Martin (referee)
This thesis is devoted to the web-page analysis and to the analysis of the accessability of financial records, that are usually part of annual reports. The first part is devoted to the theoretical basis and standards, where is stated how an airline corporation should act. In the second part, the theoretical basis is applied to concrete airlines, that are significant on the personal air-transportation market. The individual rating is stated in the conclusion. There are also concrete recommendations that should be used for raising the competitiveness of the given subject.
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Web pages comparison of airlines on the zech market
Veis, Richard ; Toman, Prokop (advisor) ; Pösinger, Martin (referee)
Hlavním tématem práce je srovnání webových stránek několika leteckých společností na českém trhu. Hlavními oddíly jsou jednak popis internetu a jeho vzniku, vytyčení kritérií pro zhodnocení jednotlivých aspektů webových prezentací, a nakonec konkrétní zhodnocení dle zvolených kritérií. Výchozím uživatelem je cestující, tomu byla kriteria uzpůsobena. Daným kritériím jsou přidělovány váhy vyjadřující jejich důležitost. K nalezeným nedostatkům jsou navrhována jednotlivá doporučení. Na konci práce je pomocí tabulky a grafu znázorněno pořadí dle úspěšnosti v analýze.
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