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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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Magneto-optical investigation of spintronic materials
Vojáček, Libor ; Flajšman, Lukáš (referee) ; Arregi Uribeetxebarria, Jon Ander (advisor)
Magnetooptický Kerrův jev představuje užitečný nástroj pro zkoumání magnetických vlastností kovových povrchů. Jeho využití při měření procesu přepínání magnetizace vnějším magnetickým polem nám může poskytnout cennou informaci o magnetické anizotropii zkoumané látky. V předložené práci se zabýváme teoretickými aspekty procesu přepínání magnetizace a změny polarizace světla při odrazu od magnetických povrchů. Dále je popsána optická sestava založená na modulaci polarizace světla schopná měřit magnetooptické veličiny s vysokou citlivostí. Tento přístroj byl sestaven modifikací již existující, podobné optické sestavy. Funkčnost zařízení byla ověřena měřeními na tenkých magnetických vrstvách. Získaná data pomáhají odhalit vlastnosti tenkých metamagnetických vrstev z FeRh, materiálu s potenciálními aplikacemi pro spintroniku.
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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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Optical and magneto-optical spectroscopy of materials with antiferromagnetic interaction
Križanová, Katarína ; Zázvorka, Jakub (advisor) ; Čermák, Petr (referee)
Title: Optical and magneto-optical spectroscopy of materials with antiferro- magnetic interaction Author: Bc. Katarína Križanová Department: Institute of Physics of Charles University Supervisor: RNDr. Jakub Zázvorka, Ph.D., Institute of Physics of Charles University Abstract: One of the goals of spintronic research is the efficient external con- trol of magnetic moment. Non-collinear antiferromagnets in the antiperovskite structure, such as Mn3NiN, show a piezomagnetic effect that can be used to utilize these materials in applications. In the strain free state, the material ex- hibit zero net magnetic moment. Using strain induced by a lattice constant mismatch between the thin layer and a substrate on which the thin film is applied on a non-zero net magnetic moment can be registered. Magneto-optical Kerr effect spectroscopy is used to investigate the non-collinear magnetic thin films. The effect of two substrate layers with resulting opposite sign of strain influencing the magnetic ordering of the antiperovskite material is studied with respect to sample temperature. Results show comparable spectral dependence with opposite sign of the Kerr effect caused by the opposite direc- tion of net magnetization moments. Ellipsometry measurements depending on sample orientation are performed to study the material...
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Optical and magneto-optical spectroscopy of materials with antiferromagnetic interaction
Križanová, Katarína ; Zázvorka, Jakub (advisor) ; Čermák, Petr (referee)
Title: Optical and magneto-optical spectroscopy of materials with antiferro- magnetic interaction Author: Bc. Katarína Križanová Department: Institute of Physics of Charles University Supervisor: RNDr. Jakub Zázvorka, Ph.D., Institute of Physics of Charles University Abstract: One of the goals of spintronic research is the efficient external con- trol of magnetic moment. Non-collinear antiferromagnets in the antiperovskite structure, such as Mn3NiN, show a piezomagnetic effect that can be used to utilize these materials in applications. In the strain free state, the material ex- hibit zero net magnetic moment. Using strain induced by a lattice constant mismatch between the thin layer and a substrate on which the thin film is applied on a non-zero net magnetic moment can be registered. Magneto-optical Kerr effect spectroscopy is used to investigate the non-collinear magnetic thin films. The effect of two substrate layers with resulting opposite sign of strain influencing the magnetic ordering of the antiperovskite material is studied with respect to sample temperature. Results show comparable spectral dependence with opposite sign of the Kerr effect caused by the opposite direc- tion of net magnetization moments. Ellipsometry measurements depending on sample orientation are performed to study the material...
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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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Magneto-optical investigation of spintronic materials
Vojáček, Libor ; Flajšman, Lukáš (referee) ; Arregi Uribeetxebarria, Jon Ander (advisor)
Magnetooptický Kerrův jev představuje užitečný nástroj pro zkoumání magnetických vlastností kovových povrchů. Jeho využití při měření procesu přepínání magnetizace vnějším magnetickým polem nám může poskytnout cennou informaci o magnetické anizotropii zkoumané látky. V předložené práci se zabýváme teoretickými aspekty procesu přepínání magnetizace a změny polarizace světla při odrazu od magnetických povrchů. Dále je popsána optická sestava založená na modulaci polarizace světla schopná měřit magnetooptické veličiny s vysokou citlivostí. Tento přístroj byl sestaven modifikací již existující, podobné optické sestavy. Funkčnost zařízení byla ověřena měřeními na tenkých magnetických vrstvách. Získaná data pomáhají odhalit vlastnosti tenkých metamagnetických vrstev z FeRh, materiálu s potenciálními aplikacemi pro spintroniku.
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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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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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