These materials are characterized by an equation that includes a hopping integral, the t-J model, itself derived from the Hubbard model. By comparing the coherence length to the London penetration depth, one can determine if these materials are Type I or Type II. A critical temperature above the boiling point of nitrogen characterizes the high-temperature type of these materials, which include cuprate perovskites like YBCO. These materials expel interior magnetic fields 
These materials are characterized by an equation that includes a hopping integral, the t-J model, itself derived from the Hubbard model. By comparing the coherence length to the London penetration depth, one can determine if these materials are Type I or Type II. A critical temperature above the boiling point of nitrogen characterizes the high-temperature type of these materials, which include cuprate perovskites like YBCO. These materials expel interior magnetic fields through the Meissner Effect, a phenomenon explained by Cooper pairs in the BCS theory. For 10 points, name these materials which exhibit zero electrical resistance.
These materials are characterized by an equation that includes a hopping integral, the t-J model, itself derived from the Hubbard model.
{superconductor}s [or word forms]