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Spatially resolved measurements of magneto-optical Kerr effect in nanostructures
Kletečka, Vojtěch ; Veis, Martin (advisor) ; Butkovičová, Dagmar (referee)
With increasing complexity of devices utilizing magnetic properties of mate- rials grows the need to characterize and further examine these properties. One of the possible ways to do this is utilizing of magnetooptical Kerr effect with Kerr microscope. In the theoretical part of this thesis is at first described response of the electromagnetic wave to the magnetic field in reflection on the ferromagnetic material and then explained the possibility of using the effect in measurements of the response. After that in experimental part is designed and constructed mea- suring system which is capable of measuring the response and this system is then tested on provided samples.
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Investigation of magnetic structures using Kerr microscopy in various configurations
Papáčková, Anežka Terezie ; Zázvorka, Jakub (advisor) ; Uhlířová, Klára (referee)
The magneto-optical Kerr effect (MOKE) is an optical non-destructive and non- invasive method used to investigate the physical properties of magnetic materials that can be further used in magneto-optical technologies. This thesis aims to describe the prin- ciples of Kerr microscopy and afterwards to describe the design and testing of a MOKE based wide-field microscope. The new feature of this microscope prototype consists of the implementation of the rotating analyser, which allows for obtaining the Kerr rotation of the studied system directly from the captured pictures with the accuracy of several milli- degrees. A high-speed CMOS camera combined with image post-processing techniques, is used to obtain high-resolution images. The configuration and accuracy of the microscope is tested by measuring with different sets of angles of crossing and the number of image accumulations. To demonstrate the setup capabilities in different configurations, we pre- sent exemplary measurements on two selected types of samples. Out-of-plane domains are observed on Pr:YIG, in-plane domains on Co:NiMnGa. 1
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Spatially resolved measurements of magneto-optical Kerr effect in nanostructures
Kletečka, Vojtěch ; Veis, Martin (advisor) ; Butkovičová, Dagmar (referee)
With increasing complexity of devices utilizing magnetic properties of mate- rials grows the need to characterize and further examine these properties. One of the possible ways to do this is utilizing of magnetooptical Kerr effect with Kerr microscope. In the theoretical part of this thesis is at first described response of the electromagnetic wave to the magnetic field in reflection on the ferromagnetic material and then explained the possibility of using the effect in measurements of the response. After that in experimental part is designed and constructed mea- suring system which is capable of measuring the response and this system is then tested on provided samples.
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Investigation of spin polarization by laser spectroscopy
Kuchařík, Jiří ; Němec, Petr (advisor) ; Veis, Martin (referee)
Spintronics is a new branch of electronics, which uses not only the charge of electron but also its spin for transfer and processing of information. For re- al applications it is necessary to understand, how the magnetic state of matter changes not only in time but also in space. This diploma thesis is therefore de- voted to the imaging of magnetic domains in ferromagnetic semiconductors by purely optical methods, which are based on the usage of the magneto-optical ef- fects. In first part of the thesis we concentrated on the optimalization of existing polarizing microscope, whose function is based solely on the polar Kerr effect. After the optimalization we try to use this setup to observe magnetic domains in ferromagnetic semiconductor GaMnAs by the means of the magnetic linear dichroism. 1
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