Morphology and strain-induced defect structure of ultrathin epitaxial Fe films on Mo(110)
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2002Citation:
Murphy, S.; Mac Mathúna, D. M.; Mariotto, G.; Shvets, I. V., Morphology and strain-induced defect structure of ultrathin epitaxial Fe films on Mo(110), Physical Review B (Condensed Matter and Materials Physics), 66, 19, 2002, 195417Download Item:
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Abstract:
Fe films in a coverage range of 0.4<~?<~4.7ML were deposited on a Mo(110) substrate in the 300<~T<~700K temperature range. It is found that growth around 300 K is mediated by the step-flow growth mechanism, in contrast with previous studies of the Fe/Mo(110) and Fe/W(110) systems, where growth at 300 K was mediated by two-dimensional island nucleation and coalescence. This difference is attributed to the slightly higher substrate temperature (between 300 and 345 K) during deposition. A transition from layer-by-layer to Stranski-Krastanov growth is observed in films grown in the 300<~T<~345K range at around a 1.8 ML coverage. Strain-relieving dislocation defects appear along the [001?] direction in the second Fe layer and develop with increasing film thickness into a dislocation network at around a 2.4 ML coverage. The dislocation defects in the second Fe layer act as preferential nucleation sites for third layer islands. At elevated temperatures (495<~T<~700K), the first and second Fe layers are formed by the step-flow growth mechanism. Subsequent coverages are characterized by the formation of distinctive wedge-shaped islands supported on an Fe monolayer. A two-dimensional dislocation network is formed in the fourth Fe layer of these islands, from an array of closely-spaced dislocation lines in the third layer. Similar to the Fe/W(110) system, the magnetic properties of these films are expected to vary significantly on the nanometer scale and they are therefore potential candidates for spin-polarized scanning tunneling microscopy studies.
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Science Foundation Ireland (SFI)
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http://people.tcd.ie/ivchvetshttp://people.tcd.ie/mariotl
http://people.tcd.ie/shmurphy
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Physical Review B (Condensed Matter and Materials Physics)66
19
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Atomic, molecular and chemical physics, thin filmsDOI:
http://dx.doi.org/10.1103/PhysRevB.66.195417Licences: