University of Leicester
Browse
Co_in_Cr_paper.pdf (557.21 kB)

Structure and magnetism in Cr-embedded Co nanoparticles

Download (557.21 kB)
journal contribution
posted on 2015-12-18, 12:10 authored by Stephen Henry Baker, M. S. Kurt, M. Roy, M. R. Lees, C. Binns
We present the results of an investigation into the atomic structure and magnetism of 2 nm diameter Co nanoparticles embedded in an antiferromagnetic Cr matrix. The nanocomposite films used in this study were prepared by co-deposition directly from the gas phase, using a gas aggregation source for the Co nanoparticles and a molecular beam epitaxy (MBE) source for the Cr matrix material. Co K and Cr K edge extended x-ray absorption fine structure (EXAFS) experiments were performed in order to investigate atomic structure in the embedded nanoparticles and matrix respectively, while magnetism was investigated by means of a vibrating sample magnetometer. The atomic structure type of the Co nanoparticles is the same as that of the Cr matrix (bcc) although with a degree of disorder. The net Co moment per atom in the Co/Cr nanocomposite films is significantly reduced from the value for bulk Co, and decreases as the proportion of Co nanoparticles in the film is decreased; for the sample with the most dilute concentration of Co nanoparticles (4.9% by volume), the net Co moment was 0.25 μ B/atom. After field cooling to below 30 K all samples showed an exchange bias, which was largest for the most dilute sample. Both the structural and magnetic results point towards a degree of alloying at the nanoparticle/matrix interface, leading to a core/shell structure in the embedded nanoparticles consisting of an antiferromagnetic CoCr alloy shell surrounding a reduced ferromagnetic Co core.

History

Citation

Journal of Physics : Condensed Matter, 2016, 28(4), 046003

Author affiliation

/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Physics and Astronomy

Version

  • AM (Accepted Manuscript)

Published in

Journal of Physics : Condensed Matter

issn

0953-8984

eissn

1361-648X

Acceptance date

2015-12-11

Copyright date

2016

Available date

2017-01-07

Publisher version

http://iopscience.iop.org/article/10.1088/0953-8984/28/4/046003/meta

Notes

The file associated with this record is under a 12-month embargo from publication in accordance with the publisher's self-archiving policy, available at http://authors.iop.org/atom/help.nsf/0/F20EC7D4A1A670AA80256F1C0053EEFF?OpenDocument. The full text may be available through the publisher links provided above.

Language

en

Usage metrics

    University of Leicester Publications

    Categories

    Keywords

    Exports

    RefWorks
    BibTeX
    Ref. manager
    Endnote
    DataCite
    NLM
    DC