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Title: Magnetite nano-islands on silicon-carbide with graphene

Abstract

X-ray magnetic circular dichroism (XMCD) measurements of iron nano-islands grown on graphene and covered with a Au film for passivation reveal that the oxidation through defects in the Au film spontaneously leads to the formation of magnetite nano-particles (i.e, Fe 3O 4). The Fe nano-islands (20 and 75 monolayers; MLs) are grown on epitaxial graphene formed by thermally annealing 6HSiC( 0001) and subsequently covered, in the growth chamber, with nominal 20 layers of Au. Our X-ray absorption spectroscopy and XMCD measurements at applied magnetic fields show that the thin film (20 ML) is totally converted to magnetite whereas the thicker lm (75 ML) exhibits properties of magnetite but also those of pure metallic iron. Temperature dependence of the XMCD signal (of both samples) shows a clear transition at T V ≈ 120 K consistent with the Verwey transition of bulk magnetite. These results have implications on the synthesis of magnetite nano-crystals and also on their regular arrangements on functional substrates such as graphene.

Authors:
 [1];  [1];  [1];  [2];  [1];  [1]
  1. Ames Lab. and Iowa State Univ., Ames, IA (United States). Dept. of Physics and Astronomy
  2. Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS), X-ray Science Division
Publication Date:
Research Org.:
Ames Laboratory (AMES), Ames, IA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1347901
Report Number(s):
IS-J-9226
Journal ID: ISSN 0021-8979; TRN: US1701029
Grant/Contract Number:
AC02-07CH11358; AC02-06CH11357
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 121; Journal Issue: 1; Journal ID: ISSN 0021-8979
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE

Citation Formats

Anderson, Nathaniel A., Zhang, Qiang, Hupalo, Myron, Rosenberg, Richard A., Tringides, Michael C., and Vaknin, David. Magnetite nano-islands on silicon-carbide with graphene. United States: N. p., 2017. Web. doi:10.1063/1.4973571.
Anderson, Nathaniel A., Zhang, Qiang, Hupalo, Myron, Rosenberg, Richard A., Tringides, Michael C., & Vaknin, David. Magnetite nano-islands on silicon-carbide with graphene. United States. doi:10.1063/1.4973571.
Anderson, Nathaniel A., Zhang, Qiang, Hupalo, Myron, Rosenberg, Richard A., Tringides, Michael C., and Vaknin, David. Thu . "Magnetite nano-islands on silicon-carbide with graphene". United States. doi:10.1063/1.4973571. https://www.osti.gov/servlets/purl/1347901.
@article{osti_1347901,
title = {Magnetite nano-islands on silicon-carbide with graphene},
author = {Anderson, Nathaniel A. and Zhang, Qiang and Hupalo, Myron and Rosenberg, Richard A. and Tringides, Michael C. and Vaknin, David},
abstractNote = {X-ray magnetic circular dichroism (XMCD) measurements of iron nano-islands grown on graphene and covered with a Au film for passivation reveal that the oxidation through defects in the Au film spontaneously leads to the formation of magnetite nano-particles (i.e, Fe3O4). The Fe nano-islands (20 and 75 monolayers; MLs) are grown on epitaxial graphene formed by thermally annealing 6HSiC( 0001) and subsequently covered, in the growth chamber, with nominal 20 layers of Au. Our X-ray absorption spectroscopy and XMCD measurements at applied magnetic fields show that the thin film (20 ML) is totally converted to magnetite whereas the thicker lm (75 ML) exhibits properties of magnetite but also those of pure metallic iron. Temperature dependence of the XMCD signal (of both samples) shows a clear transition at TV ≈ 120 K consistent with the Verwey transition of bulk magnetite. These results have implications on the synthesis of magnetite nano-crystals and also on their regular arrangements on functional substrates such as graphene.},
doi = {10.1063/1.4973571},
journal = {Journal of Applied Physics},
number = 1,
volume = 121,
place = {United States},
year = {Thu Jan 05 00:00:00 EST 2017},
month = {Thu Jan 05 00:00:00 EST 2017}
}

Journal Article:
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