A superconducting material supports a superconducting phase under an appropriate range of temperature, magnetic field and current. Those conditions, along with its gap structure and other microscopic properties, determine how it can be used.
Critical temperature alone is insufficient to compare applications. A wire may need a high critical current in a strong magnetic field, while a sensitive device may require low dissipation and well-controlled interfaces. Structural defects can pin vortices and alter current-carrying performance, making sample preparation and measurement conditions part of a useful material specification.
The superconducting intermetallic used in high-field conductors. Maintaining current-carrying connectivity and controlling strain are distinct from achieving a large upper critical field.
