Fully frustrated Ising system on a 3D simple cubic lattice: revisited

Using extensive Monte Carlo simulations, we clarify the critical behaviour of the 3D simple cubic Ising fully frustrated system. We find two transition temperatures and two long-range ordered phases. Within the present numerical accuracy, the transition at higher temperature is found to be second order and we have extracted the standard critical exponents using the finite-size scaling method. On the other hand, the transition at lower temperature is found to be First order. It is argued that entropy plays a major role on determining the low-temperature state.