Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

1 Publication
Untwinning of alloyed nanoparticles via intermediate amorphization
Järvi, T. T.; Pohl, D.; Albe, K.; Rellinghaus, B.; Schultz, L.; Fassbender, J.ORC; Kuronen, A.; Nordlund, K.
Recent experimental evidence shows that multiply twinned CuAu and FePt nanoparticles transform to single crystalline morphology under helium irradiation with keV energies [1,2]. The untwinning is rather unexpected, since it is widely accepted that under the given conditions only Frenkel pairs are formed, which do not affect the stability of twin boundaries.
We present molecular dynamics simulations revealing that the mechanism behind the transformation is based on intermediate amorphization of the particles. By comparing with irradiation simulations of elemental nanoparticles, published previously [3], as well as alloyed bulk samples and surface cascades, we show that this transformation route is only present in alloyed particles. Moreover, the observed amorphization is more efficient for twinned than single- crystalline particles, explaining, together with fast recrystallization kinetics, the observed untwinning.

[1] Dmitrieva et al., J. Appl. Phys. 97 (2005) 10N112
[2] Järvi T. T., Pohl D., et al., unpublished
[3] T. T. Järvi et al., J. Appl. Phys. 102 (2007) 124304
Keywords: magnetism, ion irradiation, binary alloys, nanoparticle, FePt
  • Poster
    16th International Conference on Ion Beam Modification of Materials, 31.08.-05.09.2008, Dresden, Germany

Publ.-Id: 11609 - Permalink