270034 VO Magnetism and Superconductivity: an introduction (2007S)
Magnetism and Superconductivity: an introduction
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Blockzeitraum: 23. April -19. Juni 2007; Vorbesprechung: 07.03.2007 um 14:00 Seminarraum d. Inst. f. Physikal. Chemie
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Ziele, Inhalte und Methode der Lehrveranstaltung
In these lectures I will provide an introduction to superconductivity in solids with the aim to present an overview/explanation of the superconductivity phenomenology and define issues of interest for superconductor design. I will first highlight the phenomenology of superconductivity (infinite conductivity, perfect diamagnetism, specific heat, type I and type II superconductors) and then address more in detail the following issues: 1) London`s equation and the magnetic field inside a superconductor 2) Ginzburg-Landau theory: the phase transition, condensation energy, 3) gauge symmetry and symmetry breaking, flux quantization 4) BCS theory of superconductivity: the electron-phonon interaction, the electron-electron interaction, the Cooper pairs, the BCS wave function. Energy gap and quasi-particle states. Predictions of the BCS theory; 5) Josephson effect and its applications; 6) Overview of superconducting materials: old and new superconductors.
Art der Leistungskontrolle und erlaubte Hilfsmittel
Mindestanforderungen und Beurteilungsmaßstab
I will address the basic concepts of magnetism in condensed matter with emphasis on magnetic material properties and phenomena which are useful in various applications. To a limited extent, the applications of magnetism are discussed in order to motivate the understanding of the physical properties and phenomena. The topics discussed in the lectures include: 7) Quantum mechanical treatment of magnetic susceptibility; susceptibility of closed shells systems, magnetism of non-interacting atoms and ions with partially filled shells, paramagnetism of localized magnetic moments. 8) Magnetism of free electron systems: Pauli paramagnetism and Landau diamagnetism. Magnetic interactions within Hartree-Fock approximation in a free electron model. 9) Interacting systems: exchange interaction. Heisenberg model, mean-field model. Spin waves and magnons in ferromagnetic crystals. The Stoner-Hubbard itinerant electron model for magnetism. 10) Magnetic interactions in diluted magnetic semiconductors.
Prüfungsstoff
Literatur
Some references: N.W. Ashcroft and M.D. Mermin: Solid State Physics (McGraw-Hill); W. Ibach, H. Lüth: Solid State Physics (Springer); G. Grosso, G. Pastori Parravicini Solid State Physics (Accademic Press); J.F. Annett: Superconductivity, superfluids and condesates (Oxford UN. Press); A. H. Morrish - The physical principles of Magnetism (Oxford Un. Press)
Zuordnung im Vorlesungsverzeichnis
F252
Letzte Änderung: Fr 31.08.2018 08:55