Critical properties of classical XY and Heisenberg models: A mean-field renormalization group study

Using mean-field renormalization group (MFRG) and surface-bulk mean-field renormalization group (SBMFRG) methods, we study the critical properties of classical Heisenberg and XY models. We show the exact result that there is no finite temperature phase transition in one dimension and very good values for critical exponents and critical temperatures are obtained for these models on cubic lattice in three dimensions.