Oxygen adsorption on ultrathin Co/Ir(1 1 1) films: Compositional anomaly

J. S. Tsay, Y. S. Chen

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

Adsorption of oxygen on ultrathin Co/Ir(1 1 1) films thinner than 4 monolayers in an ultrahigh vacuum environment was studied. For oxygen adsorption on cobalt films, the complex adsorption kinetics emerges partly due to the incorporation of oxygen. The amount of oxygen adsorbed at the surfaces is higher than that incorporated into the film as revealed from sputter profiling measurements. At room temperature the CoO layer exhibits paramagnetism and could not contribute to the remanent Kerr intensity. As oxygen exposure increases, the reduction of the Kerr intensity is due to the reduction of the effective layer for the magnetic measurements. Compared with oxygen saturated cobalt films, the concentration of adsorbed oxygen per Co atom shows an oscillatory behavior. A compositional anomaly of a great amount of adsorbed oxygen in submonolayer Co coverage occurs because of the maximized number of adsorption and incorporation sites for oxygen on the surface. A larger charge transfer between Co and oxygen was observed for thinner Co overlayers as revealed from the larger chemical shifts of Auger lines.

Original languageEnglish
Pages (from-to)3555-3559
Number of pages5
JournalSurface Science
Volume600
Issue number18
DOIs
Publication statusPublished - 2006 Sep 15

Keywords

  • Adsorption
  • Auger electron spectroscopy
  • Cobalt
  • Iridium
  • Magnetic measurements
  • Oxidation
  • Oxygen
  • Surface magneto-optic Kerr effect

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Materials Chemistry

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