Self-assembled magnetic nanostructures of CoPt3 with favoured chemical ordering

CoPt3(111) nanostructures, prepared by self-assembled growth on WSe2(0001) substrates, present a 111-oriented fcc structure with a hexagonal island shape and a relatively narrow size distribution. L1(2)- type ordering is already observed in nanostructures grown at 150 degreesC, a temperature considerably lower than that required to order CoPt3 continuous lms. This change is attributed to the nanoscopic island shape, which increases the possibilities of surface atomic arrangements provided by the different growing facets. From the superparamagnetic behavior of the nanostructures, a strong decrease of magnetic anisotropy with the occurrence of L1(2) ordering is deduced.