Magnetic Phase Transition in Two-Dimensional Ultrathin Fe Films on Au(100)

Abstract

Thin Fe films on Au(100)---including one monolayer---exhibit long-range ferromagnetic order. The temperature dependence of the magnetization, as measured with spin-polarized low-energy electron diffraction and spin-polarized secondary electron emission, shows a second-order phase transition at a thickness-dependent Curie temperature. The critical exponent $\ensuremath{\beta}$ for (1-3)-monolayer-thick films is 0.22\ifmmode\pm\else\textpm\fi{}0.05, independently of film thickness.