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Variable Field Magnetic Force Microscopy
Turčan, Igor ; Nováček, Zdeněk (referee) ; Urbánek, Michal (advisor)
The bachelor's thesis deals with magnetic force microscopy of permalloy discs in an external magnetic field. Main objectives of the thesis are design of an external magnetic field module, preparation of magnetic probes, fabrication of samples and the measurement itself. We prepared functional probes with various magnetic coatings. For the measurement in external magnetic field we fabricated probes with a~layer of magnetically hard Co and for the measurement without external magnetic field we used probes with a~layer of magnetically soft permalloy. Our probes are at least comparable with standard commercial probes. We observed the cores of magnetic vortices, using our home-coated probes with no external magnetic field and also in the external magnetic field. Further, we study the influence of the external magnetic field on nucleation of the cores of magnetic vortices. Experimental techniques used for fabrication and measurement of the samples are briefly summarized.
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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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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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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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Variable Field Magnetic Force Microscopy
Turčan, Igor ; Nováček, Zdeněk (referee) ; Urbánek, Michal (advisor)
The bachelor's thesis deals with magnetic force microscopy of permalloy discs in an external magnetic field. Main objectives of the thesis are design of an external magnetic field module, preparation of magnetic probes, fabrication of samples and the measurement itself. We prepared functional probes with various magnetic coatings. For the measurement in external magnetic field we fabricated probes with a~layer of magnetically hard Co and for the measurement without external magnetic field we used probes with a~layer of magnetically soft permalloy. Our probes are at least comparable with standard commercial probes. We observed the cores of magnetic vortices, using our home-coated probes with no external magnetic field and also in the external magnetic field. Further, we study the influence of the external magnetic field on nucleation of the cores of magnetic vortices. Experimental techniques used for fabrication and measurement of the samples are briefly summarized.
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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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Far-infrared magneto-optical measurements of superconducting NbN layer
Koláček, Jan ; Skrbek, L. ; Šindler, M. ; Tesař, Roman
Temperature dependence of far-infrared transmission of thin layer NbN deposited on SiO2 substrate has been measured at frequencies 0.40, 0.65 and 2.52 THz. The zero magnetic field data are in agreement with previous measurements. Additionally, temperature dependent transmission at 0.40 THz for parallel and perpendicular magnetic field orientation with respect to NbN layer from 1 to 10 tesla is reported. In order to interpret our data, we have calculated the transmission of the NbN layer using equations for complex conductivity. For zero magnetic field, the experimental and computed data are in good agreement. With increasing field, however, the experimental data start to deviate from the model prediction that neglects effects due to quantized vortices penetrating the superconductor. When moving, they absorb energy and affect both reflection and transmission. Presently, no way of calculating the complex conductivity in the presence of quantized vortices from the BCS theory is known.
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