Critical behavior of the surface magnetization of an isotropic Heisenberg ferromagnet: EuS(111) on Si(111)

Abstract

Magneto-optic Kerr-effect measurements (bulk sensitive) and spin-polarized low-energy electron diffraction (surface sensitive) reveal that the surface and the bulk Curie temperatures of epitaxial EuS(111) on Si(111) are identical to within 0.04 K. In the critical region of the bulk, the surface magnetization m1 of this model substance for an isotropic Heisenberg ferromagnet decreases as m1(1-TTC)1, with 1=0.720.03. This differs significantly from current theoretical estimates of 1, possibly pointing to a very strong surface anisotropy. © 1987 The American Physical Society.