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Fabrication of SiO2 by anisotropic etching of silicon
Balajka, Jan ; Kolíbal, Miroslav (referee) ; Urbánek, Michal (advisor)
The aim of the bachelor's thesis is the fabrication of silicon dioxide (SiO2) membranes on silicon (Si) substrate by anisotropic etching of silicon. Masks for anisotropic silicon etching were prepared by electron beam litography and SiO2 wet etching. Individual steps of membrane fabrication are described, including used experimental conditions. In order to optimize the fabrication process, etch rates of Si/SiO2 in several solutions were measured. Results of the measurements are included in the thesis. Fabricated membranes were characterised by optical microscopy, scanning electron microscopy and spectroscopic reflectometry. Methods used for fabrication and analysis of defined structures created by anisotropic silicon etching are briefly summarized.
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Switching vortex chirality in magnetostatically coupled permalloy nanodisks
Balajka, Jan ; Nebojsa, Alois (referee) ; Urbánek, Michal (advisor)
The diploma thesis is concerned with switching of vortex circulation in magnetic nanodisks. The results of micromagnetic simulations of hysteresis loops of individual disks with different degrees of asymmetry are presented. The influence of geometric asymmetry of the disk on the shape of the hysteresis loop is discussed as well as switching of vortex circulation in asymmetric nanodisks by external in-plane magnetic field. Simulations of pairs of magnetostatically coupled nanodisks were carried out for different interdisk distances and degrees of asymmetry. By analysing the results of the simulations, the effects of magnetostatic coupling and the asymmetry on resultant circulation of individual vortices were compared and the range of magnetostatic interaction between nanodisks of given dimensions and asymmetry was estimated. Experimental techniques used for fabrication and measurement of the samples are briefly summarized.
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Switching vortex chirality in magnetostatically coupled permalloy nanodisks
Balajka, Jan ; Nebojsa, Alois (referee) ; Urbánek, Michal (advisor)
The diploma thesis is concerned with switching of vortex circulation in magnetic nanodisks. The results of micromagnetic simulations of hysteresis loops of individual disks with different degrees of asymmetry are presented. The influence of geometric asymmetry of the disk on the shape of the hysteresis loop is discussed as well as switching of vortex circulation in asymmetric nanodisks by external in-plane magnetic field. Simulations of pairs of magnetostatically coupled nanodisks were carried out for different interdisk distances and degrees of asymmetry. By analysing the results of the simulations, the effects of magnetostatic coupling and the asymmetry on resultant circulation of individual vortices were compared and the range of magnetostatic interaction between nanodisks of given dimensions and asymmetry was estimated. Experimental techniques used for fabrication and measurement of the samples are briefly summarized.
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Fabrication of SiO2 by anisotropic etching of silicon
Balajka, Jan ; Kolíbal, Miroslav (referee) ; Urbánek, Michal (advisor)
The aim of the bachelor's thesis is the fabrication of silicon dioxide (SiO2) membranes on silicon (Si) substrate by anisotropic etching of silicon. Masks for anisotropic silicon etching were prepared by electron beam litography and SiO2 wet etching. Individual steps of membrane fabrication are described, including used experimental conditions. In order to optimize the fabrication process, etch rates of Si/SiO2 in several solutions were measured. Results of the measurements are included in the thesis. Fabricated membranes were characterised by optical microscopy, scanning electron microscopy and spectroscopic reflectometry. Methods used for fabrication and analysis of defined structures created by anisotropic silicon etching are briefly summarized.
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