Whenever a nanosystem such as an adatom, a cluster, or a nanowire spontaneously magnetizes, a crucial parameter is its magnetic anisotropy, i.e., the intrinsic preference of magnetization to lie along an easy axis. Anisotropy is important in nanosystems because it helps reduce the magnitude of thermal (``superparamagnetic'') fluctuations, it can modify the flow of current, and it can induce new phenomena, such as the quantum tunneling of magnetization. We discuss here, based on density functional calculations, the novel and unconventional feature of colossal magnetic anisotropy (CMA) -- the strict impossibility of magnetization to rotate from parallel to orthogonal direction -- which the recently predicted Pt (and Rh) nanowire magnetism should exhibit, due to a selection rule which we prove in the limit of strong spin-orbit coupling. Model calculations suggest that CMA of a Pt chain should persist also after weak adsorption on an inert substrate or surface step.
|Titolo:||Colossal magnetic anisotropy of monatomic free and deposited platinum nanowires|
|Autori:||Smogunov A; DAL CORSO A; Delin A; Weht R; and Tosatti E|
|Data di pubblicazione:||2008|
|Digital Object Identifier (DOI):||10.1038/nnano.2007.419|
|Appare nelle tipologie:||1.1 Journal article|