DC sputtering technique

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Table of contents

1 All-optical magnetization switching 
1.1 Introduction
1.2 Phenomenology of laser-induced ultrafast magnetization dynamics
1.2.1 Observation of ultrafast laser-induced demagnetization
1.2.2 Modeling of the ultrafast magnetization dynamics
1.3 All-optical switching in GdFeCo thin films
1.3.1 Experimental demonstration of all-optical switching in GdFeCo alloy films
1.3.2 Unification of helicity-dependent and heat-only switching
1.4 Novel materials for all-optical helicity-dependent switching
1.4.1 Ferrimagnetic materials
1.4.2 Ferromagnetic materials
1.5 Any general mechanism for all-optical switching ?
1.5.1 Temperature influence on the AO-HDS of ferrimagnets
1.5.2 Possible origins of the symmetry breaking for AO-HDS
1.5.3 Orientation conservation
1.6 Outlines of the thesis
2 Experimental tools and samples 
2.1 Introduction
2.2 Samples elaboration and characterization
2.2.1 DC sputtering technique
2.2.2 Light-ion irradiation
2.2.3 Magnetic characterization
2.3 Femtosecond pulsed laser
2.3.1 Femtosecond laser pumping
2.3.2 Femtosecond laser amplification
2.4 Magneto-optical Faraday microscope
2.4.1 Magneto-optical Kerr effect
2.4.2 Experimental setup
3 Domain size criterion for the observation of all-optical switching 
3.1 Introduction
3.2 Magnetic interactions and domains
3.2.1 Magnetic interactions
3.2.2 Magnetic domains and domain walls
3.2.3 Magnetization reversal in thin films
3.3 Thickness-dependence of all-optical switching in ferrimagnets and ferromagnets
3.3.1 Studied ferri- and ferro-magnets
3.3.2 Thickness-dependence of the all-optical switching in ferrimagnets
3.3.3 Thickness-dependence of the all-optical switching in ferromagnets
3.4 Domain size criterion for the observation of all-optical switching
3.4.1 Magnetic parameters for studied materials
3.4.2 Domain size calculation for ferro- and ferrimagnets
3.4.3 Conclusions
3.5 Magnetic anisotropy dependence of the all-optical switching
3.5.1 Tailoring magnetic anisotropy by light-ion irradiation
3.5.2 All-optical control of magnetization in irradiated Co/Pt multilayers .
3.6 Summary
4 Distinction between two types of all-optical switching mechanisms via magnetotransport measurements 
4.1 Introduction
4.2 Electrical characterization of AO-HDS in ferromagnetic Pt/Co/Pt Hall crosses
4.2.1 Introduction
4.2.2 Sweeping beam measurement
4.2.3 Static beam measurement with an off-centered beam
4.2.4 Static beam measurement with a centered beam
4.2.5 Summary
4.3 Electrical characterization of AOS in ferromagnetic CoFeB/MgO Hall crosses
4.3.1 Sweeping beam measurement
4.3.2 Static beam measurement with a centered beam
4.3.3 Summary
4.4 Electrical characterization of AO-HDS in ferrimagnetic TbCo Hall crosses
4.4.1 Sweeping beam measurement
4.4.2 Static beam measurement with an off-centered beam
4.4.3 Static beam measurement with a centered beam
4.4.4 Summary
4.5 Two types of all-optical switching mechanism distinguished via the anomalous Hall effect
4.5.1 Introduction
4.5.2 Single-pulse switching of GdFeCo based Hall crosses and continuous films
4.5.3 Single-pulse induced demagnetization of [Co/Pt]N and TbCo continuous film
4.5.4 Multiple-shot switching of Co/Pt and TbCo based Hall crosses
4.5.5 Discussion: Microscopic origin of multiple-pulse helicity- dependent switching
4.5.6 Summary
5 General conclusions and perspectives