The resistance of some metals, alloy and compounds will suddenly disappear at a certain temperature. And the magnetic line of force is completely excluded from the object (that is, completely diamagnetism). This phenomenon is called superconductivity, a state characterized by zero resistance and complete diamagnetism, and is called superconducting state. In the superconducting state. The DC resistance is zero, but there is still a small energy loss on AC power.
Special functional materials -> Superconducting materials -> Superconducting parameters