Kinetically-controlled superconducting material

Probes (smaller yellow patches) monitor the status of a metallic material (grey) as electrodes (larger yellow patches) deliver current to induce superconductivity. Credit: Hiroshi Oike

Condensed-matter physics

How to persuade a reluctant metal to take on a superpower

A lightning-fast burst of current prods an alloy into a superconducting state.

Exposure to extreme cold is enough to transform some materials into a superconducting state, in which they can carry electricity with no resistance. But scientists have long been frustrated by certain stubborn metals that instead react to cooling by entering a ‘competing state’: the metal’s electrons take on an energetically favourable arrangement that prevents superconductivity.

Now Hiroshi Oike, Fumitaka Kagawa and their colleagues at the RIKEN Center for Emergent Matter Science in Wako, Japan, have cooled a material so quickly that the competing state did not have time to form.

The team applied a pulse of electrical current to a metal composed of tellurium and iridium. The pulse heated the metal to more than 27˚C before cooling it to −269˚C in less than ten microseconds. The process is analogous to plunging molten metal into cold water, which preserves the metal’s structure and prevents it from weakening as it cools.

After the researchers’ intervention, the metal entered a stable superconducting state for more than a week. The technique could lead to the discovery of superconducting materials that cannot be predicted with conventional thermodynamics, the authors write.