Two-dimensional Ising transition of epitaxial Fe films grown on Ag(100).

Abstract

Fe(100) films and wedges between 2 and 4 monolayers thick were grown onto a Ag(100) single-crystal substrate. High- and low-energy electron-diffraction observations confirm the epitaxy. The magnetic phase transition near the Curie temperature ${\mathit{T}}_{\mathit{C}}$ was investigated in situ by means of the surface magneto-optic Kerr effect. The temperature dependence of the magnetization follows a universal power law of M(T)\ensuremath{\propto}(1-T/${\mathit{T}}_{\mathit{C}}$${)}_{\mathit{c}}^{\mathrm{\ensuremath{\beta}}}$ with an effective value of ${\mathrm{\ensuremath{\beta}}}_{\mathit{c}}$\ensuremath{\approxeq}1/8(0.124\ifmmode\pm\else\textpm\fi{}0.002), which indicates that the phase transition is two-dimensional Ising class. This and the observed perpendicular easy axes are attributed to the surface magnetic anisotropy.