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Preparation and testing of SNOM probes
Bobek, Juraj ; Pavera, Michal (referee) ; Spousta, Jiří (advisor)
The area of research that deals with surface modification and preparation of nanostructures is still very unexplored. And only a little contribution to this field is discussed in this bachelor thesis. Its goal is to manufacture and to test a probe made off hollow optical fibre that is used in Scanning Probe Microscopy. Optical fibre parameters in combination with proper and unique techniques allow the breakthrough off very interesting applications. It's worth mentioning the gas injection in the proximity of the surface of a sample (GIS) and thus its modification by use of electrons (FEBID), ions (FIBID) or laser beams.
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Mathematics for Electromagnetism
Rára, Michael ; Spousta, Jiří (referee) ; Doupovec, Miroslav (advisor)
The goal of this thesis is the description of elektromagnetism by means of selected parts of mathematics, in particular tensors, vector fields, integral calculus and integral theorems. Maxwell's equations will be derived by means of these notions in integral form, differential form and tensor form, we also show usefulness of tensor form of these equations.
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THE APPLICATION OF NANOMATERIALS FOR LEAD FREE SOLDERS DEVELOPMENT
Pešina, Zbyněk ; Pinkas, Jiří (referee) ; Spousta, Jiří (referee) ; Sopoušek, Jiří (advisor)
The present dissertation is motivated by the search for alternatives of lead-free soldering by nanoparticles of metals and their alloys. The research focuses on the possibility of replacing lead-free solders by nanoparticles. This issue is currently being addressed by the use of lead-free solders but their properties are not entirely equivalent to properties of lead-tin based alloys. The theoretical part of the dissertation first summarizes up-to date knowledge on the development of lead-free alloys currently used for soldering in the electronics. The work compares these lead-free solder candidates with previously used Pb-Sn alloys. The second section of the theoretical part is devoted to nanotechnology that offers possible solutions of problems associated with the use of lead-free solders. The text contains a description of the properties of nanocrystalline materials in comparison with those of compact alloys having the same chemical composition. The possibility of preparation of nanoparticles and potential problems associated with small particle sizes are also presented. Introduction of the experimental part focuses on the preparation of nanoparticles of pure metals and alloys by chemical and physical ways as well as on an instrumentation for characterisation and analysis. Attention is focused on the silver in nanoparticle form that exhibits the low temperature sintering effect, which is thermally activated by decomposition of oxide envelope covering the Ag nanoparticles. This factor is critical for low-temperature sintering and thus also for possible future applications. The thermal effects of the low sintering process were studied by methods of thermal analysis. The preparation of the Cu / Ag nano / Cu joints was carried out in-situ in inert atmosphere and under the action of atmospheric oxygen. In both cases varying conditions of thermal treatment were used. The cross sections of the prepared joints were then used for the metallographic analysis of the local mechanical properties of the resulting silver layer, for the chemical composition evaluation of the resulting layers of the joint, and for the microstructure study. Strength characteristics are represented by testing shear strength of individual joints.
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Multifunctional SNOM probes of new generation for correlative SEM/SPM measurements
Zezulka, Lukáš ; Kolíbal, Miroslav (referee) ; Spousta, Jiří (advisor)
Práce se věnuje návrhu multifunkční SNOM sondy pro korelativní SEM/SPM měření využívající dutého optického vlákna s plným jádrem. V rešerši jsou prozkoumány možné způsoby výroby SNOM hrotů na dutém optickém vlákně, využití dutých kapilár pro přívod pracovních tekutin ke vzorku a možnosti přívodu potenciálového rozdílu ke vzorku pomocí kapilár vyplněných vodivým materiálem. Dále je v práci prezentován vyvinutý způsob výroby unikátních SNOM hrotů a celý koncept je ověřen provedenými korelativními měřeními. Následně jsou diskutované problémy spojené s výrobou a měřeními.
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Correlation of electron backscatter diffraction for elastic stress mapping
Ondračka, Václav ; Kuběna, Ivo (referee) ; Spousta, Jiří (advisor)
Electron backscatter diffraction is a method that is well described and commonly used for orientation image mapping, including grain size estimation. The use of this method for measuring elastic deformation and rotations caused by plastic deformations is not so well decribed. This diploma thesis first describes the typical EBSD system. The information regarding the standard coordinate systems, grain orientation notation and system calibration is then used to create an open-source software for mapping elastic deformations and rotations inside a single grain or a monocrystal. This software uses data acquired during standard EBSD mapping on a commercial system.
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Improvement of IBAD apparatus
Urbánek, Ivan ; Nebojsa, Alois (referee) ; Spousta, Jiří (advisor)
This thesis is divided into three main parts dealing with ion beam assisted deposition. In the first part there is a brief description of the IBAD chamber at Institute of Physical Engineering of BUT. There is also a detailed description of control of the IBAD apparatus during deposition. Next part deals with measuring of deposition rates of ion sputtering in order to refine deposition of thin layers. Last part deals with planned and already finished changes that should improve quality and speed of thin layers deposition. Changes include the option of covering the substrate holder, change of the entry flange, design of new insertion chamber with multifunctional substrate holder and the option to control the deposition by computer.
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Measurement of thin films properties by imaging spectroscopy and magnetooptical Kerr effect
Plšek, Radek ; Navrátil, Karel (referee) ; Spousta, Jiří (advisor)
This thesis is divided into three main sections that deal with optical and magnetic thin films properties and their measurements techniques. Principles of the spectroscopic reflectometry and measurements of optical properties are described in the first part. Results of imaging reflectometry are most important. This technique is based on in situ monitoring of optical properties of SiO2 thin films during etching over the area cca 10 × 13 mm2. In next section magnetic properties of thin films and new apparatus built on the Institute of Physical Engineering of BUT are shown. Magnetic properties were observed by longitudinal magneto-optical Kerr effect. The construction of the device is based on a light beam with rectilinear polarization reflected from magnetic material with turned polarization. For investigation of local magnetic properties of microstructures a microscope objective focusing laser beam on the sample is used. The last part of the thesis is aimed on improving of a spin valve structure Co/Cu/NiFe. This work was done within the frame of the Erasmus project in Laboratoire Louis Néel in Grenoble. The goal was to achieve the value of GMR (Giant Magnetoresistance) as high as possible by changing of deposition parameters. This value describes the rate of resistances in different mutual directions of magnetization in trilayers.
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SNOM probes with special properties
Slabý, Vít ; Kalousek, Radek (referee) ; Spousta, Jiří (advisor)
This bachelor thesis deals with scanning near-field optical microscopy. With SNOM we examined experimentally the near field of the interference of surface plasmon polaritons (PPP) on plasmonic structures consisting of slits in a metal layer a we discuss the effect of probe characteristics on the measurement results.Effect of few characteristics is simulated numerically. Findings obtained in the previous experiments are used for the construction designing of an experimental device called NanoGIS, which should serve for the nanostructure manufacturing.
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Design of the apparatus for the measurement of the magnetic properties of the micro and nanostructures
Flajšman, Lukáš ; Dubroka, Adam (referee) ; Spousta, Jiří (advisor)
This bachelor's thesis deals with magneto-optic effects with special aim for magneto-optic Kerr effect. Presented description allows us to quantify magneto-optical observables on the basis of measuring the light intensity after the reflection from sample surface. Consequently, we use a simple physical model to unriddle the origin of the optical anisotropy induced by the external magnetic field. In the part, that deals with the design of an aparatus for measuring magneto-optical Kerr effect in longitudinal conformation, we provide necessary information to define a device capable of measuring magneto-optic observables in micro/nano scale. Last chapter i aimed to the achieved results on the thin Co films and on magnetic vortices with lateral dimensions of 1 m.
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