Ferromagnetic order at surfaces of ultrathin epitaxial fcc gamma -Fe(111)p(11) films on Cu(111).

Abstract

Electron-capture spectroscopy has been used to investigate long-ranged and short-ranged two-dimensional magnetic order at free (uncoated) surfaces of homogeneous (island-free), ultrathin fcc \ensuremath{\gamma}-Fe(111)(1\ifmmode\times\else\texttimes\fi{}1) films pseudomorphically deposited on Cu(111) substrate crystals. At 298 K, the electron-spin polarization at the surface of a four-monolayer thin fcc Fe film amounts to +16%, directly revealing the existence of long-ranged ferromagnetic order. There is evidence that short-ranged ferromagnetic order still exists at 400 K at free surfaces of two and one-monolayer thin fcc Fe films.