Peculiar magnetic behaviour and Meissner effect in two-dimensional layered Nb2C MXene

Currently, superconductivity in two-dimensional (2D) materials is a hot topic of research owing to their enormous potential applications. We have observed peculiar magnetic Meissner effect in 2D Nb2C MXene leading to signatures of superconductivity in the material with an onset transition temperature of 12.5 K. Systematically optimized chemical etching process of bulk Nb2AlC MAX phase led to the formation of 2D Nb2C MXene as confirmed using scanning electron microscope (SEM) and x-ray diffraction (XRD) indicating a significant increase in the c-lattice parameter from 13.83 Å to 22.72 Å. The Meissner effect and its unusual magnetic nature is observed using superconducting quantum interference device (SQUID: Quantum Design). Fittings of experimentally obtained lower and upper critical fields as a function of temperature to the Ginzburg-Landau (GL) theory confirms possibility of presence of type-II superconductivity in our Nb2C samples. This peculiar magnetic behaviour, observed in as-synthesized Nb2C MXene in powder form is intrinsic property of our sample. It is to be noted that we have tried to measure the transport properties of our sample but due to its powdered nature, this was not possible. We insist that this work is a significant advancement in the field of magnetism and superconductivity in 2D MXene which may be explored further to determine superconductivity by measuring the transport properties in future.