INVESTIGADORES
BRINGA Eduardo Marcial
artículos
Título:
Analytical solution of the mean field Ising model for finite systems
Autor/es:
D.S. BERTOLDI; E.M. BRINGA; E. MIRANDA
Revista:
JOURNAL OF PHYSICS CONDENSED MATTER
Editorial:
IOP PUBLISHING LTD
Referencias:
Año: 2012 vol. 24 p. 226004 - 226010
ISSN:
0953-8984
Resumen:
The Ising model for finite systems, e.g. for clusters of different sizes
and crystal lattices, was solved analytically by the mean field
approach. The magnetization was calculated from the number of accessible
microstates, using the gamma function and its derivatives, unlike the
usual solution in the microcanonical which uses the Stirling
approximation. We determined a scaling exponent of ~1/3, which shows how
the Curie temperature decreases with decreasing nanoparticle size.
Moreover, the model predicts the behaviour of surface and core regions
and it explains in simple terms several effects previously observed in
experiments and Monte Carlo simulations of small magnetic systems.