27. ON THE NATURE OF THE PHASE TRANSITION IN HELIMAGNETS

Abstract

The nature of the phase transition in body-centered tetragonal helimagnets with both XY and Heisenberg spins is studied by extensive Monte Carlo simulations. In the XY case, evidence of a first order transition associated with the loss of helical ordering is found. The dependence on the turn angle Q is shown. In the Heisenberg case, only one second order transition is found. Critical exponents α and ν are calculated using finite size scaling.