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Experimental Physics of Functional Spin Systems

Prof. Christian Back

Research Field

The research of our group is focused on the detailed understanding of magnetization dynamics in hybrid materials comprising of ultrathin magnetic layers in combination with topological materials or with materials inducing strong interfacial spin-orbit interaction. We tailor novel hybrid magnetic structures and investigate their static and dynamic magnetic properties. Among the subjects covered in our research are the dynamics in confined magnetic systems, magnonics, spin orbitronics, hybrid topological materials, high resolution magnetic microscopy as well as magnetic phase transitions in low dimensional systems.

In our group we use several techniques to examine magnetization dynamics, the propagation of spinwaves and the efficiency of charge to spin current conversion. At the heart of our research projects are various time and spatially resolved high resolution magnetic microscopy techniques in combination with microwave excitation and detection.

Address/Contact

James-Franck-Str. 1
85748 Garching b. München
efs.office@ph.tum.de
+49 89 289 12401
Fax: +49 89 289 12414

Members of the Research Group

Professor

Office

Scientists

Students

Other Staff

Teaching

Course with Participations of Group Members

Titel und Modulzuordnung
ArtSWSDozent(en)Termine
Experimentalphysik 1
eLearning-Kurs aktuelle Informationen
Zuordnung zu Modulen:
VO 4 Back, C. Di, 08:30–10:00, MI HS1
Fr, 10:00–12:00, MI HS1
Magnetism and Magnetic Materials
eLearning-Kurs
Zuordnung zu Modulen:
VO 4 Back, C.
Mitwirkende: Chen, L.
Di, 14:00–16:00, PH 2024
Do, 16:00–18:00, PH 2024
Mathematische Ergänzungen zur Experimentalphysik 1
eLearning-Kurs
Zuordnung zu Modulen:
VO 2 Höffer von Loewenfeld, P.
Leitung/Koordination: Back, C.
Mi, 12:00–14:00, PH HS1
Spin-Wave Computing
Zuordnung zu Modulen:
HS 2 Back, C.
Mitwirkende: Aqeel, A.
Exercise to Magnetism and Magnetic Materials
Zuordnung zu Modulen:
UE 2 Chen, L.
Leitung/Koordination: Back, C.
Offenes Tutorium zu Experimentalphysik 1
Zuordnung zu Modulen:
UE 2 Höffer von Loewenfeld, P. Maier, T.
Leitung/Koordination: Back, C.
Mo, 12:00–14:00, MW 2050
Di, 12:00–14:00, ZEI 0001
Übung zu Experimentalphysik 1
aktuelle Informationen
Zuordnung zu Modulen:
UE 2 Maier, T.
Leitung/Koordination: Back, C.
Termine in Gruppen
Aktuelle Themen zur Physik funktionaler Spinsysteme
Zuordnung zu Modulen:
SE 2 Back, C.
Dozentensprechstunde zu Mathematische Ergänzungen zur Experimentalphysik 1
Diese Lehrveranstaltung ist keinem Modul zugeordnet.
RE 2 Höffer von Loewenfeld, P.
Leitung/Koordination: Back, C.
FOPRA-Versuch 23: Ferromagnetische Resonanz (FMR) (AEP, KM, QST-EX)
Zuordnung zu Modulen:
PR 1 Korniienko, A. Pietanesi, L.
Leitung/Koordination: Back, C.
QuantumEngineering-Seminar
Zuordnung zu Modulen:
SE 0.2 Back, C. Pfleiderer, C. Weig, E. Do, 17:00–19:00, PH HS3
sowie einzelne oder verschobene Termine
Repetitorium zu Rechnen mit Spin-Wellen
Zuordnung zu Modulen:
RE 2
Leitung/Koordination: Back, C.
Seminar zu aktuellen Themen zum Oberflächenmagnetismus
Zuordnung zu Modulen:
SE 2 Back, C.

Offers for Theses in the Group

Construction of a spectrometer for ferromagnetic resonance for frequencies up to 65 GHz

In dieser Arbeit soll ein neues Spektrometer für Messungen mit Methoden der ferromagnetischen Resonanz im Frequenzbereich zwischen 10 - 65 GHz aufgebaut und getestet werden.

suitable as
  • Bachelor’s Thesis Physics
Supervisor: Christian Back
Electrical detection of a domain wall in FeCo films

In diesem Projekt soll der anisotrope Magneto-Widerstand verwendet werden um eine einzelne Domänenwand in ferromagnetischen Nanostrukturen aus FeCo zu detektieren.

suitable as
  • Bachelor’s Thesis Physics
Supervisor: Christian Back
High resolution magnetic microscopy using the tip enhanced anomalous Nernst effect
We want to use a tip-enhanced near-field microscope to enable high-resolution magnetic microscopy. In this experiment, the tip of a force microscope is illuminated with a laser and thus a large temperature gradient is generated locally (via the field increase at the tip). The temperature gradient generates an anomalous Nernst voltage locally, which can be detected via electrical contacts on the ferromagnetic nanostructure. With this method, it should be possible to realise magnetic microscopy with a spatial resolution of 20 nm.
suitable as
  • Master’s Thesis Condensed Matter Physics
Supervisor: Christian Back
Measurement of ferromagnetic resonance in perpendicular geometry on ferromagnet/topological insulator bi-layers
In diesem Projekt sollen temperaturabhängige Messungen der ferromagnetischen Resonanz an Ferromagnet/Topologischen Isolator Heterostrukturen durchgeführt werden. Als Funktion der Temperatur sollte es möglich sein den Anstieg der Linienbreite zu beobachten, der durch die Dominanz der topologischen Oberflächenzustände bei tiefen Temperaturen hervorgerufen wird.
suitable as
  • Bachelor’s Thesis Physics
Supervisor: Christian Back
Dynamic detection of spin-orbit torques using standing spinwave pattern
Current-induced spin-orbit torques (SOTs) in ferromagnet/nonmagnetic metal heterostructures open vast possibilities to design spintronic devices to store, process, and transmit information in a simple architecture. It is a central task to search for efficient SOT devices, and to quantify the magnitude as well as the symmetry of current-induced spin-orbit magnetic fields (SOFs). Here, we will evaluate an approach to determine the SOFs based on magnetization dynamics by means of time-resolved magneto-optic Kerr microscopy. A microwave current in a narrow Fe/GaAs (001) stripe generates an Oersted field as well as SOFs due to the reduced symmetry at the Fe/GaAs interface, and excites standing spin wave (SSW) modes because of the lateral confinement. Due to their different symmetries, the SOFs and the Oersted field generate distinctly different mode patterns. Thus, it is possible to determine the magnitude of the SOFs from an analysis of the shape of the SSW patterns. Specifically, this method, which is conceptually different from previous approaches based on line shape analysis, is phase independent and self-calibrated. It can be used to measure the current-induced SOFs in other material systems, e.g., ferromagnetic metal/nonmagnetic metal heterostructures.
suitable as
  • Master’s Thesis Condensed Matter Physics
Supervisor: Christian Back
Quantum transport in ferromagnet proximity driven exchange coupled superconducting nanowires
Wir werden Thullium Yttrium Garnet (TIG)/Supraleiter-Heterostrukturen untersuchen, um den Einfluss des Supraleiters auf die Magnetisierungsdynamik über ferromagnetische Resonanz zu erforschen. Da TIG eine senkrechte magnetische Anisotropie aufweist, wäre es interessant, den Transport im Supraleiter durch Messungen wie die I-U-Charakterisierung eines auf TIG hergestellten SQUID zu untersuchen und die Flussquantisierung im SQUID als Funktion der Magnetisierung des TIG zu quantifizieren.
suitable as
  • Bachelor’s Thesis Physics
Supervisor: Christian Back
Spin wave propagation in Bi-YIG
Spinwellenspektroskopie (elektrisch und optisch) und SQUID-Messungen sollen an ferrimagnetischen Bi-YIG Filmen durchgeführt werden, um die Eigenschaften der Filme in Bezug auf die Spindynamik zu charakterisieren. Wenn es die Zeit erlaubt, werden wir die Leistungsabhängigkeit spezifischer Spinwellen-Anregungen (MSBVW) untersuchen und die Beziehung zwischen kohärenten Spinwellen und Bose-Einstein-Magnonen (oder Magnonen bei der niedrigsten Energie) untersuchen.
suitable as
  • Bachelor’s Thesis Physics
Supervisor: Christian Back
Interplay between the spin-orbit torque and superconducting states in Ni/Bi bi-layers
Durch Magneto-Transport Messungen bei tiefen Temperaturen können sogenannte Spin-Orbit-Torques detektiert werden, die ausgenutzt werden können um die Magnetisierung von dünnen Filmen zu manipulieren. In diesem Projekt sollen Kombinationen aus ferromagnetischen Schichten und Supraleitern untersucht werden.
suitable as
  • Bachelor’s Thesis Physics
Supervisor: Christian Back
Tracing in-plane magnetization switching dynamics by time-resolved magneto-optical Kerr microscopy
The demonstration of magnetization switching induced by spin-orbit torques in a ferromagnetic metal (FM)/heavy metal (HM) bilayer has attracted tremendous attention due to possible application in magnetic random access memories (MRAM). Typically, an in-plane current sent through the heavy metal layer (e.g. Pt) gives rise to a spin accumulation at the FM/HM interface due to the spin Hall effect. The spin accumulation acts on the ferromagnet (e.g. Co) via the spin transfer torque effect and leads to magnetization dynamics and, ideally, to switching. In this Master thesis, we will use time resolved magneto-optical Kerr microscopy (TRMOKE), which is a time and spatially resolved technique, to trace the switching dynamics of an in-plane magnetized ferromagnetic metal. The following points will be addressed: 1) The Co/Pt thin films will be patterned to micrometer-size devices by using a by mask-free laser writer or by electron-beam lithography. 2) Time and spatially resolved magnetization dynamics will be measured by TRMOKE. 3) Finally, the experimental data will be compared to theory.
suitable as
  • Master’s Thesis Condensed Matter Physics
Supervisor: Christian Back

Current and Finished Theses in the Group

Anisotropic modulation of magnetic properties in GaAs/Fe/Pt by spin current
Abschlussarbeit im Masterstudiengang Physics (Applied and Engineering Physics)
Themensteller(in): Christian Back
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