Dannenberg, Antje; Gruner, Markus Ernst; Hucht, Alfred; Entel, Peter:
Surface energies of stoichiometric FePt and CoPt alloys and their implications for nanoparticle morphologies
2009
In: Physical review / B, Jg. 80 (2009), Heft 24, S. 245438
Artikel/Aufsatz in Zeitschrift2009Physik
Zentrale wissenschaftliche Einrichtungen » Center for Nanointegration Duisburg-Essen (CENIDE)
Titel:
Surface energies of stoichiometric FePt and CoPt alloys and their implications for nanoparticle morphologies
Autor(in):
Dannenberg, AntjeLSF; Gruner, Markus ErnstLSF; Hucht, AlfredLSF; Entel, PeterLSF
Erscheinungsjahr
2009
DOI:

Abstract:

We have calculated surface energies and surface magnetic order of various low-indexed surfaces of monoatomic Fe, Co, and Pt, and binary, ordered FePt, CoPt, and MnPt using density-functional theory. Our results for the binary systems indicate that elemental, Pt-covered surfaces are preferred over Fe and Co covered and mixed surfaces of the same orientation. The lowest energy orientation for mixed surfaces is the highly coordinated (111) surface. We find Pt-covered (111) surfaces, which can be realized in the L11 structure only, to be lower in energy by about 400 meV/atom compared to the mixed L10 (111) surface. We conclude that in small nanoparticles this low surface energy can stabilize the L11 structure, which is suppressed in bulk alloys. From the interplay of surface and bulk energies, equilibrium shapes of single-crystalline ordered nanoparticles and crossover sizes between the different orderings can be estimated.