50 years ago, superconductors were warming up

Superconducting temperatures have risen by about 250 degrees since the 1970s, but are still too cold to enable practical technologies.

50 years ago, superconductors were warming up
To create superconductors, physicists use diamond anvils (one shown) to crush materials at high pressures and ultracold temperatures. Researchers are searching for materials that can superconduct at ambient pressure and room temperature.

Superconductivity, the property by which certain metals lose all their electrical resistance, would be a grand thing to use technologically were it not for the extreme refrigeration necessary. Every superconductor has a transition temperature above which it becomes an ordinary conductor. Most transition temperatures are near absolute zero. [Scientists] are discovering metals with higher transition temperatures.

Transition temperatures continue to creep upward. In 2018, physicists reported that a compound of lanthanum and hydrogen under extreme pressure showed signs of superconductivity up to about −20° Celsius — the highest for any superconductor (SN: 10/13/18, p. 6). But the squeeze and relative chill makes these materials impractical for widespread use, so the hunt for a material that superconducts at room temperature and closer to atmospheric pressure continues. A debunked 2023 claim for such a material has some scientists advocating for new standards for identifying superconductivity (SN: 12/16/23 & 12/30/23, p. 22).