Epitaxial growth of Ni on Cu( [formula omitted]) with the assistance of O-surfactant and its magnetism compared to Ni/Cu( [formula omitted])

• Published in: Surface science Vol. 531; no. 1; pp. 53 - 67
• Main Authors: Nünthel, R, Gleitsmann, T, Poulopoulos, P, Scherz, A, Lindner, J, Kosubek, E, Litwinski, Ch, Li, Z, Wende, H, Baberschke, K, Stolbov, S, Rahman, T.S
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 10-05-2003; Amsterdam Elsevier Science; New York, NY
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Copper; Epitaxy; Exact sciences and technology; Growth; Magnetic films; Magnetic properties and materials; Magnetic properties of monolayers and thin films; Magnetic properties of surface, thin films and multilayers; Nickel; Physics; Scanning tunneling microscopy; Magnetic films; Scanning tunneling microscopy; Nickel; Copper; Growth; Epitaxy; Kerr magneto-optical effect; Magnetic hysteresis; Solid-solid interfaces; Experimental study; Structure relaxation; STM; Magnetic thin films; EXAFS spectrometry; Ferromagnetic resonance; Surface reconstruction; Metallic thin films; Transition elements; Crystal faces; LEED; Magnetic properties
• ISSN: 0039-6028; 1879-2758
• DOI: 10.1016/S0039-6028(03)00438-2

The growth of Ni films deposited on a reconstructed (√2×2√2)R45° O/Cu(0
0
1) is examined. It is shown that deposition of Ni changes the surface symmetry to c(2
×
2) and that oxygen always floats on the film surface. No NiO is formed. Surface roughness decreases and the growth mode is closer to ideal layer-by-layer, as compared to that of Ni/Cu(0
0
1) indicating a surfactant activity of oxygen. Furthermore, the critical thickness for dislocation formation is larger than that for Ni/Cu(0
0
1), which points to a less defective film structure. The improved growth patterns are accompanied by a shift of the spin reorientation transition from in- to out-of-film plane by about 5 monolayers. In the film plane, the easy axis of the magnetization switches from the [1
1
0] direction for Ni/Cu(0
0
1), to the [1
0
0] direction for Ni on preoxidized Cu. We attribute these characteristics to modifications of the film surface by the floating oxygen.