Journal of Physics A Mathematical and General
Dipolar interaction in random-field systems
Thomas Nattermann
Abstract
It is shown that the dipolar interaction breaks the universality of the low-temperature and critical behaviour between the random-field Ising model (RFIM) and the diluted antiferromagnet in an external field (DAFF). For the RFIM, the dipolar interaction changes the roughness and the critical exponents; in particular, the upper critical dimensionalities are diminished by one. The dipolar interaction exerts no influence on these exponents in the DAFF, nor on the lower critical dimensionality d l =2 of both systems.