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 journalArticle

1 Scopus citations

Abstract

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
JournalNanomaterials
Volume9
Issue number10
DOIs
StatePublished - Oct 2019

Keywords

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

ASJC Scopus subject areas

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

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    Tosun, O., Abel, F. M., Balasubramanian, B., Skomski, R., Sellmyer, D. J., & Hadjipanayis, G. C. (2019). Structure and magnetism of Co2Ge nanoparticles. Nanomaterials, 9(10), [1371]. https://doi.org/10.3390/nano9101371