Advanced Seminar in Physics / Hautpseminar

Location: Faculty room 2.136
Time: Block Seminar
Wednesday 22. May 2024
Thursday 23. May 2024

Submission of written summary (8-10 Pages) by 30. June 2024

Regeln Physikalisches Hauptseminar SoSe2024

Guidelines Advanced Seminar SoSe24

• Definition and properties from thermodynamics
• Landau theory of phase transition
• Critical behavior in second order phase transition
• Examples in magnetic material and properties
• Examples of first and second order phase transitions in condensed matter 

References:
Theory of First order phase transitions by K. Binder
First order magneto-structural phase transition and associated multi-functional properties in magnetic solids, https://iopscience.iop.org/article/10.1088/0953-8984/25/18/183201/meta
Introduction to Phase transitions and critical phenomena by H. E. Stanley

• What is magnetic monopole? Does it exist in the universe?
• Electro-magnetic properties
• Do we see them in condensed matter/magnetic materials (spin ice compound)
• Residual entropy in spin ice compounds
• Ingredients of glass formation in condensed matter
• What is the difference between spin glass and cluster glass state
• Examples of spin glass and cluster glass states in real materials
• How to identify a glassy system and distinguish between spin glass and cluster glass?

References:
Magnetic monopoles in spin ice by C. Castelnovo et al, https://www.nature.com/articles/nature06433
Measurement of the charge and current of magnetic monopoles in spin ice by S. T. Bramwel, https://www.nature.com/articles/nature08500
Spin glasses: An experimental Introduction by J. A. Mydosh
Spin glasses: redux: an updated experimental survey
https://iopscience.iop.org/article/10.1088/0034-4885/78/5/052501
and references therein

• What is the meaning of Geometrical frustration
• What are the preliminary experimental signatures of a Quantum spin liquid state?
• Examples observed in solid state physics and how they are detected in experiment?

References:
Savary, L.; Balents, L. "Quantum spin liquids: a review". Reports on Progress in Physics. 80, 016502 (2017).
Yi Zhou, Kazushi Kanoda, and Tai-Kai Ng, Quantum spin liquid states, Rev. Mod. Phys. 89, 025003 (2017)

• What is magnetic Skyrmions?
• Some examples where it is observed?
• Application in Spintronic devices
• What are Spin waves, magnon and Spinons?
• Where are they observed?
• Properties
• How these excitations can be probed in real materials?

References:
Magnetic Skyrmions: Basic properties and potential applications by S. Li et al
https://onlinelibrary.wiley.com/doi/full/10.1002/idm2.12072
Physical foundation and basic properties of magnetic skyrmions, by A. N. Bogdanov, Nature reviews (2020)
https://www.nature.com/articles/s42254-020-0203-7
https://www.nature.com/articles/nphys3347
https://iopscience.iop.org/article/10.1088/0034-4885/29/1/307
https://www.google.de/books/edition/Spin_Waves/ehN6-ubvKwoC?hl=de&gbpv=1&dq=spin+waves&printsec=frontcover

• What is ultra-cold atom?
• How we can manipulate them to mimic a real system?
• Benefits of using them. How to different structures of ultra-cold atoms can be used to study fundamentals of condensed matter physics?
• Any limitations?

References:
https://physicsworld.com/a/quantum-magnetism-simulated-using-ultracold-fermions/
https://www.nature.com/articles/nphys2259
https://physics.aps.org/articles/v14/159

• Femtosecond optical pulse, how to produce ultra-fast laser pulses
• How it can be used to manipulate a magnetic state? What is Optical switching of a magnetic state?
• Application in spintronic devices

References:
https://www.nature.com/articles/s41563-023-01499-z
https://www.nature.com/articles/s41563-023-01554-9
https://doi.org/10.1063/1.4958846
https://doi.org/10.1103/RevModPhys.82.2731

• Why do we use neutrons for magnetic materials?
• How do diffraction methods work?
• What are elastic and inelastic neutron scatterings and how they are useful to understand a magnetic system?
• Examples of applications in real materials

References:

Neutron Diffraction: Principles, Instrumentation and application
https://www.researchgate.net/publication/321586078_Neutron_diffraction_Principles_Instrumentation_and_application
Neutron Diffraction by Paramagnetic and Antiferromagnetic Substances by C. G. Shull et al (1951)
https://journals.aps.org/pr/abstract/10.1103/PhysRev.83.333
Application of neutron powder diffraction by Eric. H. Kisi, Oxford series

• Why do we use muons?
• How to produce them?
• How to use muons to probe magnetic state?

References:
Muon spin spectroscopy, by A. D. Hiller (review article), https://www.nature.com/articles/s43586-021-00089-0
Blundell, S., De Renzi, R., Lancaster, T. & Pratt, F. Introduction to Muon Spectroscopy(Oxford Univ. Press, 2021).

• What is Terahertz spectroscopy?
• How to produce Terahertz radiation?
• Energy scales involved?
• Some examples how it can be used to probe a magnetic material?

References:
Terahertz spectroscopy: Principles and applications by Susan L. Dexhemeir
Review of recent progress on THz spectroscopy of quantum materials: Superconductors, magnetic and topological materials, by Arnab Bera et al, https://link.springer.com/article/10.1140/epjs/s11734-021-00216-8
and references therein

• Basic principle of electron spin resonance techniques
• What do you mean by Quality factor of a cavity?
• Different types of electron spin resonance spectroscopy?
• How these techniques can be used to study materials?
• Application in various fields

References:
Electron spin resonance, by Charles P. Poole
Electron spin resonance, by Abragam, B. Bleaney

• What are NV centers?
• How to create NV centers?
• Application in magnetometry

References:
Creation of NV centers by Chemical vapor deposition….. by T. Luo et al, New Journal of Physics (2022), https://iopscience.iop.org/article/10.1088/1367-2630/ac58b6
Nitrogen-vacancy centers: Physics and application, https://link.springer.com/article/10.1557/mrs.2013.18

• Volatile and non-volatile memory
• Memory devices
• Race track memory device

References:
Magnetic memory: Fundamentals and technology by D. D. Tang and Y. J. Lee, Cambridge university press.
Magnetoresistive random access memory: Present and Future by S. Ikegawa et al, https://ieeexplore.ieee.org/document/8976130

• Superconductivity: basic properties
• Why it levitates?
• How and where it is used?

References:
Superconductivity: A very short introduction by Stephen Blundell
Current state of magnetic levitation and its applications in polymers: A review
https://www.sciencedirect.com/science/article/abs/pii/S0925400521001015
M. Hermansen et al., “Magnetic levitation by rotation,” Phys. Rev. Appl. 20, 044036 (2023).

• Source of Earth magnetism
• Strength of Earth’s magnetic field
• Effect on Human being and on life in general

References:
Introduction to Geomagnetism by United state geometrical survey
https://www.usgs.gov/programs/geomagnetism
https://www.nature.com/subjects/geomagnetism