2006/11/04 by Guo‐meng Zhao, Zhao, Guo-meng, Pieder Beeli +1
Materials Science · #Boron and Carbon Nanomaterials Research #Carbon Nanotubes in Composites #FOS: Physical sciences #Graphene research and applications #Strongly Correlated Electrons (cond-mat.str-el) #Superconductivity (cond-mat.supr-con)
paper · pdf · doi:10.48550/arxiv.cond-mat/0611110
openalex publication_date 2006/11/04 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We report magnetic measurements up to 1100 K on a multi-walled carbon nanotube mat sample using a Quantum Design vibrating sample magnetometer. In an ultra-low field (H = -0.02 Oe), we find a very large paramagnetic susceptibility (up to 12.7% of 1/4pi) at 1100 K and a very large diamagnetic susceptibility (at least 8.4% of -1/4pi) at 482 K. A small magnetic field (2.1 Oe) completely suppresses the diamagnetic susceptibility at 482 K and reduces the paramagnetic susceptibility at 1100 K by a factor of over 20. We rule out explanations based on magnetic contaminants, instrument artifacts, and orbital diamagnetism. The magnetic data are inconsistent with any known physical phenomena except for granular superconductivity. The present results suggest the existence of an unknown new physical phenomenon or superconductivity with an ultra-high transition temperature.