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Physical properties of doped and non-doped Tb3Fe5O12 studied by optical spectroscopies
Vančík, Michal ; Veis, Martin (advisor) ; Mistrík, Jan (referee)
This thesis focuses on systematic study of optical and magneto-optical properties of non-doped and doped Tb3Fe5O12 thin films, on gadolinium gallium garnet and silicon substrates. Spectroscopic ellipsometry measurements were performed to obtain optical properties, thicknesses and surface roughness values of studied samples. The magneto- optical properties were investigated using the Kerr and Faraday effect measurements. Obtained experimental data were used to calculate the spectral dependence of the off- diagonal components of permittivity tensor. The results were compared with literature, and the effect of doping was discussed. On three samples, the spectral magneto-optical Kerr rotation hysteresis loops were measured, for the purpose of separating the individual contributions of sublattices. The analysis revealed that the method is probably insensitive to sublattice contributions but is sensitive to the contributions of regions with different magnetic anisotropy within the deposited layer. 1
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Dynamic change in optical response of nanostructures
Vančík, Michal ; Veis, Martin (advisor) ; Zázvorka, Jakub (referee)
Title: Dynamic change in optical response of nanostructures Author: Michal Vančík Institute: Institute of Physics of Charles University Supervisor: RNDr. Martin Veis, Ph.D., Institute of Physics of Charles University Abstract: At the present time, properties of thin layers and multilayered nanos- tructures are intensively reseacrched. Because of different properties than bulk materials, thin layers have found application in various fields and play a key role in many technologies. Nanostructures containing GdOxare intensively studied since their properties can be modified by voltage application. It is assumed, that this change is caused by migration of ions in the structure. This thesis conducts re- search on multilayered structures, whose optical response changes reversibly by applying voltage. In these samples, the change is likely caused by migration of hydrogen ions into the GdOx layer. The goal of this thesis is to describe the opti- cal properties of individual layers of the structure and to describe the dynamic change in optical properties. The measurements were conducted with the help of spectroscopic ellipsometry, which allowed in situ voltage application. Keywords: spectroscopic ellipsometry, gadolinium oxide, multilayered nanostruc- tures, in situ
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