  Extensive Monte Carlo simulations in the semi-grand-canonical ensemble are
used to study the critical behavior of a three-dimensional compressible Ising
model with antiferromagnetic interactions under constant volume conditions.
Elastic forces between spins are introduced by the Stillinger-Weber potential
and energy parameters are chosen in such a way that antiparallel spin ordering
is favored, analogous to the antiferromagnetic coupling in the rigid Ising
Hamiltonian. All the quantities analyzed strongly indicate that the system
remains in the universality class of the standard (rigid) three-dimensional
Ising model, in contrast with theoretical predictions.
