Article Review: Anomalous Meissner Effect in Multiband Superconductors

As a material transitions below its critical temperature, a defining characteristic of superconductivity is the Meissner effect, which is the removal of magnetic fields from the material. Within the Ginzburg-Landau and BCS models, this effect is thoroughly comprehended in traditional (single-band) superconductors. Disruptions to this standard pattern of behavior have been detected in multiband superconductors like MgB₂ and superconductors based on iron. Anomaly vortex clustering, mixed-phase vortex states, and paramagnetic Meissner responses are all examples of such phenomena. Type-1.5 superconductivity, giant paramagnetic Meissner responses, and implications for advanced superconducting applications are the main topics of this paper's review of recent experimental and theoretical results on the anomalous Meissner effect in multiband superconductors.