According to a paper published in Nature, researchers from the University of Manchester have discovered record-high magnetoresistance in graphene under ambient conditions. The team used high-quality graphene and tuned it to its intrinsic state, creating a plasma of fast-moving “Dirac fermions” that exhibited surprisingly high mobility despite frequent scattering. Both the high mobility and neutrality of this Dirac plasma are crucial components for the reported giant magnetoresistance.

Typically, researchers have to cool materials to liquid-helium temperatures to observe strong magnetoresistance responses. However, the team found that graphene exhibits a powerful response, reaching above 100% in magnetic fields of standard permanent magnets. Graphene exhibits a giant linear magnetoresistance in fields above a few Tesla, which is weakly temperature dependent, and this high-field magnetoresistance is again record-breaking.

In addition to the record magnetoresistivity, the researchers found that, at elevated temperatures, neutral graphene becomes a so-called “strange metal.” The behavior of strange metals is poorly understood and remains a mystery currently under investigation worldwide. The Manchester work adds more mystery to the field by showing that graphene exhibits a giant linear magnetoresistance in fields above a few Tesla, which is weakly temperature dependent.

References

• The University of Manchester. (2023, April 12). Wonder material graphene claims yet another superlative. The University of Manchester; The University of Manchester. https://www.manchester.ac.uk/discover/news/wonder-material-graphene-claims-yet-another-superlative/
• Xin, N., Lourembam, J., Kumaravadivel, P., Kazantsev, A. E., Wu, Z., Mullan, C., Barrier, J., Geim, A. A., Grigorieva, I. V., Mishchenko, A., Principi, A., Fal’ko, V. I., Ponomarenko, L. A., Geim, A. K., & Berdyugin, A. I. (2023). Giant magnetoresistance of Dirac plasma in high-mobility graphene. Nature, 616(7956), 270–274. https://doi.org/10.1038/s41586-023-05807-0