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Paramagnetic transitions and weak-diamagnetism in sulfur-doped buckypapers and graphene-oxide composites.
- Source :
-
Diamond & Related Materials . Mar2022, Vol. 123, pN.PAG-N.PAG. 1p. - Publication Year :
- 2022
-
Abstract
- The appearance of coexisting ferromagnetic and superconductive phenomena in graphite‑sulfur and amorphous carbon‑sulfur composites has recently attracted an important attention. In this work we propose a novel re-investigation of the carbon‑sulfur doping mechanism performed by employing carbon nanotube networks (cm-scale buckypapers) and graphene-oxide films as host-materials. In the buckypaper-case, the presence of multiple sulfidation processes involving formation of 1) carbon‑sulfur and 2) metal-sulfide phases was demonstrated. Presence of carbon‑sulfur bonding was identified by employing both Raman spectroscopy and X-ray photoelectron spectroscopy. The conductive and magnetic properties of the sulfur-rich areas within the buckypaper were also investigated. An enhanced carbon‑sulfur bonding was then identified in sulfur-doped graphene-oxide films. In this latter case we demonstrate an almost complete annihilation of ferromagnetic-signals. ESR-spectroscopy of this second-type of system revealed the appearance of a paramagnetic transition for g ~ 2.08 at T ~ 77 K, possibly originating from the carbon‑sulfur bonding. A weak enhancement in the diamagnetic component could be interestingly detected below T ~ 60 K as a consequence of sulfur doping, after subtraction of the percolative ferromagnetic signals. [Display omitted] • We investigate carbon-sulfur doping by employing CNT- networks and graphene-oxide as host-materials. • In the buckypaper-case, formation of carbon-sulfur and metal-sulfide phases was demonstrated. • The conductive and magnetic properties of the sulfur-rich areas were investigated. • Carbon-sulfur bonding was identified also in sulfur-doped graphene-oxide films • Annihilation of ferromagnetic-signals is demonstrated, with appearance of a paramagnetic transition for g~2.08 (T~77K) • A weak enhancement in the diamagnetic component could be interestingly detected below T ~ 60K [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 09259635
- Volume :
- 123
- Database :
- Academic Search Index
- Journal :
- Diamond & Related Materials
- Publication Type :
- Academic Journal
- Accession number :
- 155727413
- Full Text :
- https://doi.org/10.1016/j.diamond.2022.108853