American Chemical Society, Nano Letters, 6(12), p. 2732-2739, 2012
DOI: 10.1021/nl204374v
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Direct chemical and structural characterization of transient iron-nickel alloy nanowires was performed at subnanometer spatial resolution using probe spherical aberration-corrected scanning transmission electron microscopy and electron energy-loss spectroscopy. Nanowires with diameter less than 2 nm retaining their nominal bulk alloy composition were observed. In some cases, the nanowires were oxidized. Before rupture, a nanojunction as thin as three atoms in width could be imaged. The time-dependent structural analyses revealed the nanowire rupture mechanisms. It is found that the atoms on the {111} planes were the easiest to be removed by electron irradiation and fluctuations between low-energy and high-energy facets were observed. The hitherto unknown rich variety of structural and chemical behavior in alloyed magnetic nanojunctions should be considered for understanding their physical properties.