The critical current density Jc of a superconducting material is the maximum current density that the material can carry without losing its superconducting properties. Temperature plays a significant role in determining the critical current density of a superconducting material.As the temperature of a superconducting material increases, its critical current density decreases. This is because superconductivity is a low-temperature phenomenon, and as the temperature rises, the material's superconducting properties begin to degrade. The superconducting state is maintained by the formation of Cooper pairs, which are pairs of electrons that are bound together by lattice vibrations phonons . At higher temperatures, the thermal energy becomes sufficient to break these Cooper pairs, leading to a decrease in the critical current density.When the temperature reaches the critical temperature Tc of the superconducting material, the material undergoes a phase transition from the superconducting state to the normal non-superconducting state. At this point, the critical current density drops to zero, and the material loses its superconducting properties.In summary, the critical current density of a given superconducting material decreases as the temperature increases, and the material loses its superconducting properties when the temperature reaches its critical temperature.