The Meissner effect demonstrated by levitating a magnet earlier mentioned a cuprate superconductor, which can be cooled by liquid nitrogen Less than some situations, for instance very very low temperatures, some ceramics show high-temperature superconductivity (in superconductivity, "high temperature" indicates previously mentioned thirty K). The reason for this isn't comprehended, https://magbeads04703.thechapblog.com/38106392/termokoppel-options