The Physics Society of Iran Iranian Journal of Physics Research 1682-6957 7 1 2019 11 26 Critical properties of the classical Heisenberg and XY models : A mean field renormalization group study Critical properties of the classical Heisenberg and XY models : A mean field renormalization group study 1 6 560 FA A. Sadeghi F. Shahbazi Journal Article 2019 11 26  Using both mean field renormalization group (MFRG) and Surface-Bulk MFRG (SBMFRG), we study the critical behavior of the classical Heisenberg and XY models on a simple cubic lattice. Critical temperatures as well as critical exponents, characteristic the universality classes of these two models were calculated, analytically for1, 2, 3 and 4 spin clusters. The results are in good agreement with higher accurate methods such as Monte Carlo and High- temperature series.  Using both mean field renormalization group (MFRG) and Surface-Bulk MFRG (SBMFRG), we study the critical behavior of the classical Heisenberg and XY models on a simple cubic lattice. Critical temperatures as well as critical exponents, characteristic the universality classes of these two models were calculated, analytically for1, 2, 3 and 4 spin clusters. The results are in good agreement with higher accurate methods such as Monte Carlo and High- temperature series. https://ijpr.iut.ac.ir/article_560_a9a6653e48976138166de32772b1bf40.pdf