Regensburg 2000 – wissenschaftliches Programm

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AM: Magnetismus

AM 13: Postersitzung: Dünne Schichten (1–22), Magnetowiderstand (23–40), Phasenübergänge (41–55), Mikromagnetismus (56–68), Spektroskopie (69–77), Nanokristalline Materialien (78–82), Anisotropie (83–86), Schmelzen (87–90), Weitere Bereiche (91–100)

AM 13.22: Poster

Dienstag, 28. März 2000, 16:00–20:00, A

Dipolar interactions in superconductor-ferromagnet heterostructures — •Jaime Santos¹, Erwin Frey², and Franz Schwabl¹ — ¹Institut für Theoretische Physik T34, Physik Department der Technische Universität München, James Franck Strasse, 85747 Garching, Germany — ²Lyman Laboratory of Physics, Harvard University, Cambridge, MA 02138, USA

We consider a simple model for a superlattice composed of a thin magnetic film placed between two bulk superconductors. The magnetic film is modelled by a planar but otherwise arbitrary distribution of magnetic dipoles and the superconductors are treated in the London approximation. Due to the linearity of the problem, we are able to compute the magnetic energy of the film in the presence of the superconductors. We show that for wavelenghts which are much smaller than the London penetration depth, the magnetic energy is unchanged with respect to the film in free space, whereas in the case of long wavelengths compared to the London penetration depth, the magnetic energy ressembles the energy of a distribution of magnetization in a two dimensional space. This result could be verified experimentally by studying the thermodynamic properties of superlattices composed of superconductors and ferromagnetic materials [1].

[1] B. Y. Jin and J. B. Ketterson, Adv. in Phys. 38, 189 (1989).