The three-dimensional, three-state Potts Model in an External Field
  We analyze the critical behaviour of the three-dimensional, three-state Potts model in the presence of an external ordering field. From a finite size scaling analysis on lattices of size up to 70**3 we determine the critical endpoint of the line of first order phase transitions as (b_c, h_c) =(0.54938(2), 0.000775(10)). We determine the relevant temperature like and symmetry breaking directions at this second order critical point and explicitly verify that it is in the universality class of the three-dimensional Ising model. 
Frithjof Karsch and Sven Stickan