Scientists have developed classification systems to better understand and utilize superconductors. The two most common criteria are based on critical temperature and response to magnetic fields.
Based on critical temperature (Tc), superconductors are classified as either low-temperature superconductors (LTS) or high-temperature superconductors (HTS). LTS are typically metals and alloys like NbTi and Nb3Sn. With critical Tc usually below 25 K (-248℃), they require cooling with expensive liquid helium. However, due to their stability and well-understood properties, they remain the primary choice for superconducting magnets in applications like MRI scanners and particle accelerators. HTS, primarily copper oxides (e.g., YBCO) and iron-based compounds, have critical temperatures above the boiling point of liquid nitrogen (77 K or -196℃). This allows for cooling with far cheaper liquid nitrogen, drastically lowering the cost barrier and making large-scale applications like lossless power transmission and maglev systems more economically feasible.
