We present experimental data on the magnetic properties of atomically thin fee (gamma-phase) Fe films (1-6 atomic layer nominal thickness) epitaxially grown on Cu84Al16(100) obtained by linear magnetic dichroism in the angular distribution of Fe 3p core photoelectrons excited by linearly polarized synchrotron radiation. The sign and magnitude of the Fe 3p photoemission magnetic asymmetry indicates the onset of in-plane ferromagnetism at 2.5(2) monolayer (ML) thickness of gamma-Fe. The Curie temperature is 288(2) K for 4 ML thickness. The magnetic splitting of the Fe 3p mj core hole sublevels is 1.10(2) eV, i.e., the same value as measured for a bcc-Fe(100) surface where large surface and near-surface enhanced moments contribute. These results characterize the epitaxial gamma-Fe on Cu84Al16(100) as a high-spin ferromagnet for thickness up to 4 ML, with an average magnetic moment per iron atom of 2.5(1)mu(B). A phase transition occurs between 4 and 5 ML thickness: the magnetic order of the pseudomorphic gamma-Fe film decreases consistently with the breaking into two phases with the deeper layers in a low-spin and/or antiferromagnetic phase and surface restricted ferromagnetism, similar to the case of gamma-Fe/Cu(100).
Magnetism of atomically thin fcc Fe overlayers on an expanded fcc lattice: Cu84Al16(100)
1998
Abstract
We present experimental data on the magnetic properties of atomically thin fee (gamma-phase) Fe films (1-6 atomic layer nominal thickness) epitaxially grown on Cu84Al16(100) obtained by linear magnetic dichroism in the angular distribution of Fe 3p core photoelectrons excited by linearly polarized synchrotron radiation. The sign and magnitude of the Fe 3p photoemission magnetic asymmetry indicates the onset of in-plane ferromagnetism at 2.5(2) monolayer (ML) thickness of gamma-Fe. The Curie temperature is 288(2) K for 4 ML thickness. The magnetic splitting of the Fe 3p mj core hole sublevels is 1.10(2) eV, i.e., the same value as measured for a bcc-Fe(100) surface where large surface and near-surface enhanced moments contribute. These results characterize the epitaxial gamma-Fe on Cu84Al16(100) as a high-spin ferromagnet for thickness up to 4 ML, with an average magnetic moment per iron atom of 2.5(1)mu(B). A phase transition occurs between 4 and 5 ML thickness: the magnetic order of the pseudomorphic gamma-Fe film decreases consistently with the breaking into two phases with the deeper layers in a low-spin and/or antiferromagnetic phase and surface restricted ferromagnetism, similar to the case of gamma-Fe/Cu(100).I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
