Surfactant effect of oxygen in epitaxial γ-Fe/Cu(0 0 1)–O(22×2)R45°

Growth mode of epitaxial ultrathin γ-Fe film on the Cu(0 0 1) substrate with O22×2R45° reconstruction surface has been investigated via reflection high energy electron diffraction (RHEED) observation. The γ-Fe structure and surface O2×2R45° reconstruction were kept till 45 monoatomic layers (ML) with the streak pattern as proof of non-island growth mode. All oxygen atoms adsorbed on Cu(0 0 1) are floated onto 45 ML γ-Fe surface considering from the RHEED patterns. The oxygen in the state of Cu(0 0 1)–O22×2R45° reconstruction surface exhibited a strong surfactant function for the γ-Fe growth on the Cu(0 0 1) with stabilizing effect on the film. We succeeded to prepare relatively thick and pure γ-Fe film on Cu(0 0 1) by this method. Magnetization of a series of γ-Fe films was measured as a function of Fe thickness. A part of γ-Fe layer shows non-magnetism in the low spin state.