Critical behavior of multiferroic hexagonal R MnO 3

Using a microscopic model and a Green's function technique we have studied the critical behavior of some multiferroics such as hexagonal R MnO 3 . The temperature dependence and the external field dependence of the magnetization and susceptibility are determined. The critical exponents β and γ are calculated. Applying the scaling laws α , δ , and ν are also obtained. The critical exponents are in very good agreement with the existing experimental data.