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Unusual magnetic transition and enhanced diamagnetism in highly oriented pyrolytic graphite with long-range stacking-order

Song, Jiaxin, Dai, Zhiquan, Wang, Shanling, Kermani, Milad, Gao, Shuai, Wen, Jiqiu, Gu, Aiqun, He, Yi, Grasso, Salvatore, Corrias, Anna, and others. (2022) Unusual magnetic transition and enhanced diamagnetism in highly oriented pyrolytic graphite with long-range stacking-order. Diamond and Related Materials, . ISSN 0925-9635. (doi:10.1016/ j .diamond.2022. l 09163) (KAR id:95415)

Abstract

The recent observations of unusual superconductive effects in highly oriented pyrolytic graphite (HOPG) and twisted bi-layer, tri-layer and multilayer graphene materials have attracted an important attention. In this work we present a novel investigation on the relationship between structural ordering and magnetism in HOPG. Orientation dependent X-ray diffraction and temperature dependent magnetometry allowed for the identification of those HOPG samples exhibiting a long-range ordering along the c-axis. ZFC and FC magnetic curves acquired from T ~ 2 K to 300 K revealed a significant temperature-dependent variation of the diamagnetic component. By analyzing the ZFC/FC magnetic-curves (through magnetic moment subtraction methods) we identify the presence of a weak magnetic transition in the T range from 200 K to 2 K. The possible origin of the observed magnetization-trend is interpreted in relation to contributions arising from 1) disorder-rich locally-twisted-interfaces and 2) those internal graphitic sublattices exhibiting negative thermal expansion. Interestingly, magnetization against field measurements acquired at T ~ 50 K (max. field of 150 Oe) revealed the presence of a weak ferromagnetic-like hysteresis. Disappearance of the unusual ZFC/FC signal-splitting was instead found in those magnetic curves acquired from other HOPG samples with higher degree of disorder (short-range-ordering along the c-axis). This second category of samples was found to exhibit a disorder-mediated re-entrant spin-glass-like ferromagnetic behavior.

Item Type: Article
DOI/Identification number: 10.1016/ j .diamond.2022. l 09163
Subjects: Q Science
Divisions: Divisions > Division of Natural Sciences > Chemistry and Forensics
Funders: National Natural Science Foundation of China (https://ror.org/01h0zpd94)
Depositing User: Anna Corrias
Date Deposited: 13 Jun 2022 14:00 UTC
Last Modified: 04 Jun 2024 23:00 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/95415 (The current URI for this page, for reference purposes)

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