Ultrathin alumina film on Cu–9at%Al(111)

Effect of temperature on the initial stages of oxidation of γ-Al4Cu9(110)

“…In addition, weak polar streaks were observed indicating that oxide domains could take all orientations, in addition to the favored one which gave rise to the sixton spots. This differs from results reported in the literature, in which well contrasted patterns corresponding to a well crystallised oxide are observed following oxidation at high temperature [6][7][8][9][10][11][12]. Therefore in the present work, direct oxidation at 925 K was performed in an attempt to improve the crystalline quality of the oxide film.…”

“…The lack of any extra spots which could be ascribed to a well-ordered oxide layer following 1500 L oxygen dosing at 925 K contrasts with previous studies reported in the literature for which well-defined new patterns were observed after oxidation of Cu-9%atAl(1 1 1) at similar temperatures [6][7][8][9][10][11][12]. Moreover, the persistence of a reasonably well contrasted LEED pattern corresponding to the clean surface could indicate a strong decrease of the sticking coefficient with increasing temperature.…”

“…When oxidation is performed at higher temperatures (up to 995 K), a (7 √ 3 × 7 √ 3)R30 • pattern is appearing which has been ascribed to the formation of a ␥-Al 2 O 3 aluminium oxide film having the orientation relationship Al 2 O 3 < 100 > (1 1 1)//Cu-9 %atAl < 110 > (1 1 1) [6][7][8][9][10][11]. Finally, moderate oxidation at high temperature (100 L at 953 K) leads to the formation of a thin aluminium oxide film (0.5 nm thick) having a structure similar to that observed on NiAl(1 1 0) and an overall stoichiometry Al 2 O 2.6 [12]. Although ␣-Cu Al solid solutions have been extensively studied, much less attention has been devoted so far to oxidation of Cu-Al intermetallics.…”

Growth of thin epitaxial alumina films onto Ni(111): an electron spectroscopy and diffraction study

“…[3] Another nickel-containing alloy suitable for alumina layer creation is the Ni 3 Al(111) surface, [4] and a further candidate support for creation of ultrathin alumina layers is Cu-9at.%Al. [5,6] In all these systems, aluminum atoms diffusing from the bulk of the binary alloy and segregating on the surface are oxidized in an oxygen-enriched environment. The rate of surface segregation and the surface mobility of aluminum atoms are controlled by the temperature of the substrate, which is usually elevated.…”

Metastable surface oxide on CoGa(100): Structure and stability

“…The formation of surface oxides is not restricted to noble-metal surfaces: ultrathin, epitaxial oxide layers with a thickness in the subnanometer regime, and a well-defined interface to the substrate form under controlled conditions by the selective oxidation of alloys, i.e., NiAl, [2][3][4][5][6][7][8] FeAl, 9 CoGa, 10,11 and Cu-Al. 12 Such oxide films are used as insulating barriers in magnetic tunnel junctions 13 and are known to play a critical role in the device performance. For instance, spin-dependent electron tunneling was shown to occur through a gallium oxide layer used as an insulating tunnel barrier.…”