Indirect exchange coupling between magnetic adatoms in carbon nanotubes
Citation:
Costa, A. T., Jr.; Kirwan, D. F.; Ferreira, M. S., Indirect exchange coupling between magnetic adatoms in carbon nanotubes, Phys. Rev. B, 72, 8, 2005, 085402-Download Item:
Indirect exchange.pdf (published (publisher copy) peer-reviewed) 147.9Kb
Abstract:
The long-range character of the exchange coupling between localized magnetic moments indirectly mediated by the conduction electrons of metallic hosts can play a significant role in determining the magnetic order of low-dimensional structures. Here we consider how this indirect coupling influences the magnetic alignment of adatoms attached to the walls of carbon nanotubes. A general expression for the indirect coupling in terms of single-particle Green functions is presented. Contrary to the general property that magnetic moments embedded in a metal display Friedel-like oscillations in their magnetic response, calculated values for the coupling across metallic zigzag nanotubes show monotonic behavior as a function of the adatom separation. Rather than an intrinsic property, the monotonicity is shown to reflect a commensurability effect in which the coupling oscillates with periods that coincide with the lattice parameter of the nanotube host. Such a commensurability effect does not dominate the coupling across semiconducting zigzag or metallic armchair nanotubes. We argue that such a long-range character in the magnetic interaction can be used in future spintronic devices.
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http://people.tcd.ie/ferreirmDescription:
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Author: FERREIRA, MAURO
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Phys. Rev. B72
8
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