Ferromagnetic hysteresis and structural recrystallization in turbostratic graphite

Mahsa Fayazi; Bingyan Liu; Li Lei; Gao Shuai; Omololu Odunmbaku; Shanling Wang; Yi He; Filippo S. Boi

doi:10.1088/2053-1591/ab3abe

Ferromagnetic hysteresis and structural recrystallization in turbostratic graphite

Mahsa Fayazi, Bingyan Liu, Li Lei, Gao Shuai, Omololu Odunmbaku, Shanling Wang, Yi He, Filippo S. Boi

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

5 Citations (Scopus)

Abstract

The recent observation of controllable ferromagnetic and superconductive features in highly oriented pyrolytic graphite (HOPG) has attracted significant attention towards application of ferromagnetic carbon materials in data recording and computing technology. In this work we report the observation of ferromagnetic ordering in two turbostratic graphite samples by employing in situ T-XRD, VSM, EDX, T-EPR and Raman Spectroscopy. Existence of room temperature ferromagnetic hysteresis in both the analyzed samples is shown. As indicated by complementary (1) SEM/EDX (2) T-EPR and (3) Raman Spectroscopy analyses, these signals appear to be induced by the defect sites in the samples. However a possible role of the turbostratic arrangement of the carbon layers in this effect can not be excluded. By employing Rietveld refinements and T-XRD we have also investigated the changes in the structure of the turbostratic graphite phase with the increase of the temperature from 298 K to 673 K. Magnetometry was further employed to investigate the magnetic ordering in the graphitic structure of pre-annealed and post-annealed samples.

Original language	English
Article number	105612
Journal	Materials Research Express
Volume	6
Issue number	10
DOIs	https://doi.org/10.1088/2053-1591/ab3abe
Publication status	Published - 28 Aug 2019
Externally published	Yes

Keywords

defects
ferromagnetism
graphite
turbostratic stacking

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10.1088/2053-1591/ab3abe

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title = "Ferromagnetic hysteresis and structural recrystallization in turbostratic graphite",

abstract = "The recent observation of controllable ferromagnetic and superconductive features in highly oriented pyrolytic graphite (HOPG) has attracted significant attention towards application of ferromagnetic carbon materials in data recording and computing technology. In this work we report the observation of ferromagnetic ordering in two turbostratic graphite samples by employing in situ T-XRD, VSM, EDX, T-EPR and Raman Spectroscopy. Existence of room temperature ferromagnetic hysteresis in both the analyzed samples is shown. As indicated by complementary (1) SEM/EDX (2) T-EPR and (3) Raman Spectroscopy analyses, these signals appear to be induced by the defect sites in the samples. However a possible role of the turbostratic arrangement of the carbon layers in this effect can not be excluded. By employing Rietveld refinements and T-XRD we have also investigated the changes in the structure of the turbostratic graphite phase with the increase of the temperature from 298 K to 673 K. Magnetometry was further employed to investigate the magnetic ordering in the graphitic structure of pre-annealed and post-annealed samples.",

keywords = "defects, ferromagnetism, graphite, turbostratic stacking",

author = "Mahsa Fayazi and Bingyan Liu and Li Lei and Gao Shuai and Omololu Odunmbaku and Shanling Wang and Yi He and Boi, {Filippo S.}",

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doi = "10.1088/2053-1591/ab3abe",

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T1 - Ferromagnetic hysteresis and structural recrystallization in turbostratic graphite

AU - Fayazi, Mahsa

AU - Liu, Bingyan

AU - Lei, Li

AU - Shuai, Gao

AU - Odunmbaku, Omololu

AU - Wang, Shanling

AU - He, Yi

AU - Boi, Filippo S.

PY - 2019/8/28

Y1 - 2019/8/28

N2 - The recent observation of controllable ferromagnetic and superconductive features in highly oriented pyrolytic graphite (HOPG) has attracted significant attention towards application of ferromagnetic carbon materials in data recording and computing technology. In this work we report the observation of ferromagnetic ordering in two turbostratic graphite samples by employing in situ T-XRD, VSM, EDX, T-EPR and Raman Spectroscopy. Existence of room temperature ferromagnetic hysteresis in both the analyzed samples is shown. As indicated by complementary (1) SEM/EDX (2) T-EPR and (3) Raman Spectroscopy analyses, these signals appear to be induced by the defect sites in the samples. However a possible role of the turbostratic arrangement of the carbon layers in this effect can not be excluded. By employing Rietveld refinements and T-XRD we have also investigated the changes in the structure of the turbostratic graphite phase with the increase of the temperature from 298 K to 673 K. Magnetometry was further employed to investigate the magnetic ordering in the graphitic structure of pre-annealed and post-annealed samples.

AB - The recent observation of controllable ferromagnetic and superconductive features in highly oriented pyrolytic graphite (HOPG) has attracted significant attention towards application of ferromagnetic carbon materials in data recording and computing technology. In this work we report the observation of ferromagnetic ordering in two turbostratic graphite samples by employing in situ T-XRD, VSM, EDX, T-EPR and Raman Spectroscopy. Existence of room temperature ferromagnetic hysteresis in both the analyzed samples is shown. As indicated by complementary (1) SEM/EDX (2) T-EPR and (3) Raman Spectroscopy analyses, these signals appear to be induced by the defect sites in the samples. However a possible role of the turbostratic arrangement of the carbon layers in this effect can not be excluded. By employing Rietveld refinements and T-XRD we have also investigated the changes in the structure of the turbostratic graphite phase with the increase of the temperature from 298 K to 673 K. Magnetometry was further employed to investigate the magnetic ordering in the graphitic structure of pre-annealed and post-annealed samples.

KW - defects

KW - ferromagnetism

KW - graphite

KW - turbostratic stacking

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U2 - 10.1088/2053-1591/ab3abe

DO - 10.1088/2053-1591/ab3abe

M3 - Article

AN - SCOPUS:85071671322

SN - 2053-1591

VL - 6

JO - Materials Research Express

JF - Materials Research Express

IS - 10

M1 - 105612

ER -

Ferromagnetic hysteresis and structural recrystallization in turbostratic graphite

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Keywords

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