# Boundary critical behaviour of two-dimensional random Ising models.

**F. Igloi**

Research Institute for Solid State Physics, H-1525 Budapest,

P.O.Box 49, Hungary

and

Institute for Theoretical Physics, Szeged University

H-6720 Szeged, Hungary

** P. Lajko**

Institute for Theoretical Physics, Szeged University

H-6720 Szeged, Hungary

**Selke, W.**

Institut für Theoretische Physik, Technische Hochschule Aachen,

D-52056 Aachen, Germany

** F. Szalma**

Institute for Theoretical Physics, Szeged University

H-6720 Szeged, Hungary

### Abstract:

Using Monte Carlo techniques and a star-triangle transformation, Ising
models with random, 'strong' and 'weak', nearest-neighbour
ferromagnetic couplings on a square lattice with a (1,1) surface
are studied near the phase transition. Both surface and
bulk critical properties are investigated. In particular, the
critical exponents of the surface magnetization, of
the correlation lenght, and of the critical surface correlations
are analysed.

cond-mat/9711182