Probing atomic structure in magnetic core/shell nanoparticles using synchrotron radiation

DOI: 10.1088/0953-8984/22/38/385301

Authors: S. H. Baker (University of Leicester) , M. Roy (University of Leicester) , S. C. Thornton (University of Leicester) , M. Qureshi (University of Leicester) , C. Binns (University of Leicester)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Journal Of Physics: Condensed Matter , VOL 22 (38)

State: Published (Approved)
Published: September 2010

Abstract: Core/shell Fe/Cu and Fe/Au nanoparticles were prepared directly by deposition from the gas phase. A detailed study of the atomic structure in both the cores and shells of the nanoparticles was undertaken by means of extended absorption fine structure (EXAFS) measurements. For Fe/Cu nanoparticles, a Cu shell ∼20 monolayers thick appears similar in structure to bulk Cu and is sufficient to cause the structure in the Fe core to switch from body centred cubic (bcc; as in bulk Fe) to face centred cubic. This is not the case for thinner Cu shells, 1–2 monolayers in thickness, in which there is a considerable contraction in nearest-neighbour interatomic distance as the shell structure changes to bcc. In Fe/Au nanoparticles, the crystal structure in the Fe core remains bcc for all Au thicknesses although there is some stretching of the lattice. In thin Au shells ∼2 monolayers thick, there is strong contraction in interatomic distances. There does not appear to be significant alloying at the Fe/Au interface.

Subject Areas: Physics


Instruments: I18-Microfocus Spectroscopy