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Kontrola magnetické anizotropie v multivrstvách Pt/Co/Pt
Nowak, Lukáš ; Veis, Martin (advisor)
This thesis aims to explore the effect of in situ ion gun etching on magnetic proper- ties, such as perpendicular magnetic anisotropy, of Pt/Co/Pt multilayers. Perpendicular magnetic anisotropy is of interest due to its importance in spintronic application. Calibration spectroscopic ellipsometry measurements of Pt and Co layers to obtain sputter yields of respective magnetron targets were performed as a first step. After that, ten Pt/Co/Pt multilayers with different Co and top Pt layer thicknesses were prepared. Five of these samples were etched by the ion gun, mounted inside of the magnetron chamber, during different stages of the deposition. To characterize the prepared samples, experimental and modeled Kerr rotation spectra were confronted. This provided an insight into the cross-sections of the investigated samples. Magnetic hysteresis loops measured by vibrating sample magnetometer and Kerr rotation setup demonstrated higher coercive field and change of the slope of the loop induced by ion etching. When compared to the obtained cross-sections, a correlation between the change of magnetic loops and intermixing of Pt and Co at the interface was visible. This intermixing was higher in samples treated by the ion gun. 1
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Kontrola magnetické anizotropie v multivrstvách Pt/Co/Pt
Nowak, Lukáš ; Veis, Martin (advisor) ; Uhlířová, Klára (referee)
This thesis aims to explore the effect of in situ ion gun etching on magnetic proper- ties, such as perpendicular magnetic anisotropy, of Pt/Co/Pt multilayers. Perpendicular magnetic anisotropy is of interest due to its importance in spintronic application. Calibration spectroscopic ellipsometry measurements of Pt and Co layers to obtain sputter yields of respective magnetron targets were performed as a first step. After that, ten Pt/Co/Pt multilayers with different Co and top Pt layer thicknesses were prepared. Five of these samples were etched by the ion gun, mounted inside of the magnetron chamber, during different stages of the deposition. To characterize the prepared samples, experimental and modeled Kerr rotation spectra were confronted. This provided an insight into the cross-sections of the investigated samples. Magnetic hysteresis loops measured by vibrating sample magnetometer and Kerr rotation setup demonstrated higher coercive field and change of the slope of the loop induced by ion etching. When compared to the obtained cross-sections, a correlation between the change of magnetic loops and intermixing of Pt and Co at the interface was visible. This intermixing was higher in samples treated by the ion gun. 1
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Study of martensitic tranformation in Co doped NiMnGa films by optical and magnetooptical methods
Nowak, Lukáš ; Veis, Martin (advisor) ; Hamrle, Jaroslav (referee)
Martenzitic transformation is responsible for multiferroic behaviour of mag- netic shape memory effect. However, the origin of the transformation is not yet fully understood. Magnetic shape memory materials in general offer broad spectrum of possible applications. NiMnGa is the prototype compound of these materials. Particular changes in the electronic structure are the origin of marten- zitic transformation which is the key to magnetic shape memory effect. There- fore, the optical and magneto-optical methods are the ideal tools for its analysis. Studied samples were prepared using magnetron sputtering on MgO substrate. Measurements of the Kerr effect at polar configuration and normal light in- cidence were done using rotating analyzer method. Experimental results, in- cluding spectral ellipsometry and temperature dependent measurements, were compared with theoretical models and then discussed. 1
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