Extinction of ferromagnetism in highly ordered pyrolytic graphite by annealing

Xiaochang Miao; Sefaattin Tongay; Arthur F. Hebard

doi:10.1016/j.carbon.2011.11.040

Extinction of ferromagnetism in highly ordered pyrolytic graphite by annealing

Xiaochang Miao, Sefaattin Tongay, Arthur F. Hebard

Research output: Contribution to journal › Article › peer-review

20 Scopus citations

Abstract

We report that the ferromagnetism of highly ordered pyrolytic graphite (HOPG) samples as measured by hysteretic magnetization loops can be diminished and eventually extinguished with sufficiently long high vacuum anneals at temperatures on the order of 2300 °C. Concomitant with the extinction of ferromagnetism, we observe an anneal-induced increase in grain size (accompanied by possible edge reconstruction) confirmed by X-ray diffraction measurements and improved transport properties, including lower in-plane and out-of-plane resistivity, higher electron and hole mobility and improved charge compensation. The implied reduction of defects and vacancies by annealing suggests that the ferromagnetism of pristine HOPG is correlated with localized states located at zigzag edges, vacancies and related defects.

Original language	English (US)
Pages (from-to)	1614-1618
Number of pages	5
Journal	Carbon
Volume	50
Issue number	4
DOIs	https://doi.org/10.1016/j.carbon.2011.11.040
State	Published - Apr 2012
Externally published	Yes

ASJC Scopus subject areas

General Chemistry
General Materials Science

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10.1016/j.carbon.2011.11.040

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title = "Extinction of ferromagnetism in highly ordered pyrolytic graphite by annealing",

abstract = "We report that the ferromagnetism of highly ordered pyrolytic graphite (HOPG) samples as measured by hysteretic magnetization loops can be diminished and eventually extinguished with sufficiently long high vacuum anneals at temperatures on the order of 2300 °C. Concomitant with the extinction of ferromagnetism, we observe an anneal-induced increase in grain size (accompanied by possible edge reconstruction) confirmed by X-ray diffraction measurements and improved transport properties, including lower in-plane and out-of-plane resistivity, higher electron and hole mobility and improved charge compensation. The implied reduction of defects and vacancies by annealing suggests that the ferromagnetism of pristine HOPG is correlated with localized states located at zigzag edges, vacancies and related defects.",

author = "Xiaochang Miao and Sefaattin Tongay and Hebard, {Arthur F.}",

note = "Funding Information: This work is supported by the National Science Foundation (NSF) under Contract Number 1005301 (AFH) and by the Office of Naval Research (ONR) under Contract Number 00075094 (ST). The authors appreciate useful discussions with Bill Appleton and technical support by the Nanoscience Institute for Medical and Engineering Technology at the University of Florida. ",

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doi = "10.1016/j.carbon.2011.11.040",

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journal = "Carbon",

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T1 - Extinction of ferromagnetism in highly ordered pyrolytic graphite by annealing

AU - Miao, Xiaochang

AU - Tongay, Sefaattin

AU - Hebard, Arthur F.

N1 - Funding Information: This work is supported by the National Science Foundation (NSF) under Contract Number 1005301 (AFH) and by the Office of Naval Research (ONR) under Contract Number 00075094 (ST). The authors appreciate useful discussions with Bill Appleton and technical support by the Nanoscience Institute for Medical and Engineering Technology at the University of Florida.

PY - 2012/4

Y1 - 2012/4

N2 - We report that the ferromagnetism of highly ordered pyrolytic graphite (HOPG) samples as measured by hysteretic magnetization loops can be diminished and eventually extinguished with sufficiently long high vacuum anneals at temperatures on the order of 2300 °C. Concomitant with the extinction of ferromagnetism, we observe an anneal-induced increase in grain size (accompanied by possible edge reconstruction) confirmed by X-ray diffraction measurements and improved transport properties, including lower in-plane and out-of-plane resistivity, higher electron and hole mobility and improved charge compensation. The implied reduction of defects and vacancies by annealing suggests that the ferromagnetism of pristine HOPG is correlated with localized states located at zigzag edges, vacancies and related defects.

AB - We report that the ferromagnetism of highly ordered pyrolytic graphite (HOPG) samples as measured by hysteretic magnetization loops can be diminished and eventually extinguished with sufficiently long high vacuum anneals at temperatures on the order of 2300 °C. Concomitant with the extinction of ferromagnetism, we observe an anneal-induced increase in grain size (accompanied by possible edge reconstruction) confirmed by X-ray diffraction measurements and improved transport properties, including lower in-plane and out-of-plane resistivity, higher electron and hole mobility and improved charge compensation. The implied reduction of defects and vacancies by annealing suggests that the ferromagnetism of pristine HOPG is correlated with localized states located at zigzag edges, vacancies and related defects.

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Extinction of ferromagnetism in highly ordered pyrolytic graphite by annealing

Abstract

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