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DS: Dünne Schichten

DS 33: Postersitzung

DS 33.12: Poster

Dienstag, 18. März 1997, 16:15–17:45, Aula

Finite-size effects in layered magnetic systems — •Dragi Karevski and Malte Henkel — Laboratoire de Physique des Matériaux, Université Henri Poincaré Nancy I, B.P. 239, F - 54506 Vandœuvre lès Nancy, Frankreich

Thermal and magnetic effects in a system consisting of thin layers of coupled Ising spins with S=1/2 and S=1 are considered. The specific heat and the correlation length display maxima at two different temperatures. It is discussed in what sense these maxima can be interpreted as a finite-size rounding of a thermodynamic singularity associated with a phase transition. The connection with ordinary, extraordinary and special surface phase transitions is made. In 2D, the surface critical exponents are calculated from conformal invariance. The bulk and surface finite-size scaling of the order parameter profiles at the transition points is discussed. In 2D, an exact scaling function for the profiles is suggested through conformal invariance arguments for the (extra)ordinary transition.

[1] D. Karevski und M. Henkel, preprint cond-mat/9610079