Structure and magnetism of Co2Ge nanoparticles

Onur Tosun, Frank M. Abel, Balamurugan Balasubramanian, Ralph Skomski, David J. Sellmyer, George C. Hadjipanayis

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


The structural and magnetic properties of Co2Ge nanoparticles (NPs) prepared by the cluster-beam deposition (CBD) technique have been investigated. As-made particles with an average size of 5.5 nm exhibit a mixture of hexagonal and orthorhombic crystal structures. Thermomagnetic measurements showed that the as-made particles are superparamagnetic at room temperature with a blocking temperature (TB) of 20 K. When the particles are annealed at 823 K for 12 h, their size is increased to 13 nm and they develop a new orthorhombic crystal structure, with a Curie temperature (TC) of 815 K. This is drastically different from bulk, which are ferromagnetic at cryogenic temperatures only. X-ray diffraction (XRD) measurements suggest the formation of a new Co-rich orthorhombic phase (OP) with slightly increased c/a ratio in the annealed particles and this is believed to be the reason for the drastic change in their magnetic properties.

Original languageEnglish (US)
Article number1371
Issue number10
StatePublished - Oct 2019


  • Cluster deposition
  • Curie temperature
  • Magnetic nanoparticles
  • Magnetocrystalline anisotropy

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Materials Science(all)


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