A metal made of five different atoms is like a soup with bits of carrot, peas, potato, onion, and meat floating in it. Each bit is its own element: chromium, vanadium, titanium, niobium, and tantalum. Such an alloy is called high-entropy: there is no single order, and the atoms are mixed almost randomly.

Usually, magnetism and superconductivity are at odds. A magnetic atom in a superconductor is like a fly in the ointment: it breaks up the pairs of electrons that carry current without resistance. Chromium is exactly such a magnetic element. But in this alloy, superconductivity survives. At a temperature of about 2.3 K (minus 271 degrees Celsius), the alloy begins to conduct current without losses.

The scientists tested how the superconducting state is structured. It turned out that the electron pairs behave almost as in the classical BCS theory — the one that explains superconductivity in simple metals. This is surprising for such a disordered alloy. Another surprise: superconductivity does not break time-reversal symmetry, meaning processes run the same forward and backward. This is a rare and important property.

Such an alloy is a great platform for studying how disorder, magnetism, and superconductivity coexist. Perhaps in the future, this will help create superconductors that are not afraid of magnetic fields and impurities.