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Stephan Geprägs

Phone
+49 89 289-14225
Room
E-Mail
stephan.gepraegs@mytum.de
Links
Page in TUMonline
Group
Technical Physics

Courses and Dates

Offered Bachelor’s or Master’s Theses Topics

Einstellung der Größe des Spin-Hall-Magnetwiderstands

The exchange of spin angular momentum between the localized magnetic moments of a magnetically ordered insulator and the spin polarization of the conduction electrons in an adjacent metallic electrode with large spin-orbit coupling gives rise to interfacial spin mixing. This manifests itself as a characteristic angular dependence of the metal’s resistivity on the magnetization direction of the insulator’s magnetic sublattices, denoted as “spin Hall magnetoresistance (SMR)”. The effect was first observed in ferrimagnetic Y3Fe5O12/Pt thin film heterostructures and recently also reported in antiferromagnetic NiO/Pt and α-Fe2O3/Pt. While the phase of the SMR oscillations is well understood and explained by theory, their amplitude, however, is still a matter of debate, since various extrinsic as well as intrinsic parameters play a crucial role. The goal of this master’s thesis is to study the correlation of the SMR amplitude to the density of magnetic ions and their spin magnetic moments in different magnetically ordered insulating oxides.

We are looking for a master student interested in thin film technology for the fabrication and investigation of magnetic insulator/normal metal bilayer structures. The master project will provide a comprehensive introduction into laser molecular beam epitaxy (laser-MBE) as well as electron beam physical vapor deposition, high-resolution X-ray diffraction (HRXRD), atomic force microscopy (AFM), superconducting quantum interference device (SQUID) magnetometry, photolithography, and angle-dependent magnetotransport measurements.

suitable as
  • Master’s Thesis Condensed Matter Physics
  • Master’s Thesis Applied and Engineering Physics
  • Master’s Thesis Quantum Science & Technology
Supervisor: Rudolf Gross
Oxidische Heterostrukturen für Experimente mit reinen Spinströmen

Pure spin currents are generated and/or detected via the spin Hall and inverse spin Hall effect in heavy metals. These two effects crucially depend on the magnitude of the spin-orbit interaction. The goal of this thesis is to investigate the spin Hall physics in oxide systems, where large spin orbit interaction is prevailing like in the transition metal oxides. In particular, the realization of epitaxial multilayers of a spin Hall active material and a magnetically ordered insulator are a major task of this research project. Such all-oxide epitaxial structures are of current interest to better understand the underlying physics of pure spin current transport in heterostructures.

We are looking for an enthusiastic master student to work on this pure spin current physics related project. A crucial part of the thesis is the growth of oxide multilayers using laser-MBE under in-situ growth monitoring. The properties of these multilayers will then be investigated by structural, magnetic and magnetotransport techniques. As a next step, the tunability of relevant spin transport properties via the growth conditions will be analyzed

suitable as
  • Master’s Thesis Condensed Matter Physics
  • Master’s Thesis Applied and Engineering Physics
  • Master’s Thesis Quantum Science & Technology
Supervisor: Rudolf Gross
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