TY - JOUR
T1 - Unusual butterfly-shaped magnetization signals and spin-glass-like behaviour in highly oriented pyrolytic graphite
AU - Taallah, Ayoub
AU - Wen, Jiqiu
AU - Wang, Shanling
AU - Grasso, Salvatore
AU - He, Yi
AU - Xia, Jia Chen
AU - Shuai, Gao
AU - Odunmbaku, Omololu
AU - Corrias, Anna
AU - Boi, Filippo S.
N1 - Publisher Copyright:
© 2020 Elsevier Ltd
PY - 2020/10/15
Y1 - 2020/10/15
N2 - We report a novel investigation on the relationship between magnetic-ordering and graphitic-structure in highly-oriented-pyrolytic-graphite (HOPG). By employing orientation-dependent-X-ray-diffraction, Raman-spectroscopy and temperature-dependent-superconductive-quantum-interference-device (T-SQUID) we examined the presence of ferromagnetic- and superconductive-ordering in HOPG systems with 1) disordered (HOPG1, containing carbon-vacancy-rich weak-Bernal-stacking and Moiré-superlattices with θmisfit ∼ 0.5°) and 2) ordered (HOPG2, containing higher-degree of Bernal-stacking and Moiré-superlattices with θmisfit ∼ 0.5°, 0.8°, 11°) graphitic-layer-arrangement. A perfect-HOPG is expected to exhibit a diamagnetic-response to an applied-magnetic-field. Instead, additional 1) ferromagnetic-signals presenting a characteristic width-enhancement with the field increasing in HOPG1 and 2) complex butterfly-shaped ferromagnetic signals in HOPG2, are demonstrated. Temperature-dependent-magnetometry evidenced further the presence of randomly oriented ferromagnetic clusters originating from topological disorder in both HOPG1 and HOPG2. These magnetic signals were explained on the basis of the percolative-type model.
AB - We report a novel investigation on the relationship between magnetic-ordering and graphitic-structure in highly-oriented-pyrolytic-graphite (HOPG). By employing orientation-dependent-X-ray-diffraction, Raman-spectroscopy and temperature-dependent-superconductive-quantum-interference-device (T-SQUID) we examined the presence of ferromagnetic- and superconductive-ordering in HOPG systems with 1) disordered (HOPG1, containing carbon-vacancy-rich weak-Bernal-stacking and Moiré-superlattices with θmisfit ∼ 0.5°) and 2) ordered (HOPG2, containing higher-degree of Bernal-stacking and Moiré-superlattices with θmisfit ∼ 0.5°, 0.8°, 11°) graphitic-layer-arrangement. A perfect-HOPG is expected to exhibit a diamagnetic-response to an applied-magnetic-field. Instead, additional 1) ferromagnetic-signals presenting a characteristic width-enhancement with the field increasing in HOPG1 and 2) complex butterfly-shaped ferromagnetic signals in HOPG2, are demonstrated. Temperature-dependent-magnetometry evidenced further the presence of randomly oriented ferromagnetic clusters originating from topological disorder in both HOPG1 and HOPG2. These magnetic signals were explained on the basis of the percolative-type model.
UR - http://www.scopus.com/inward/record.url?scp=85086411114&partnerID=8YFLogxK
U2 - 10.1016/j.carbon.2020.05.104
DO - 10.1016/j.carbon.2020.05.104
M3 - Letter
AN - SCOPUS:85086411114
SN - 0008-6223
VL - 167
SP - 85
EP - 91
JO - Carbon
JF - Carbon
ER -