Abstract
The semi-infinite Ising model, for S=(1/2) and with an arbitrary number of surface magnetic couplings different from the bulk J, is solved in the mean-field approximation. Exact expressions for the critical couplings ,C leading to a surface Curie temperature higher than the bulk are obtained. The value for in the semi-infinite crystal is obtained by means of a continued-fraction method. The model is applied to explain recent experimental results on the (0001) surface of gadolinium.
- Received 13 November 1984
DOI:https://doi.org/10.1103/PhysRevB.31.7146
©1985 American Physical Society