A recent discovery in a study of room-temperature superconductivity, if succeeded, could make the dream of super-efficient long-distance electricity transmission and levitating trains a little closer to reality.

Whereas physicists understand how standard superconductors can operate at nearly 275 degrees Celsius below water’s freezing point, the mechanism behind high-temperature superconductors, which function at up to 140 degrees warmer than absolute zero, remains mysterious.

The researchers have also made their new paper available there. Certain parts of the material showed signs of the Josephson effect, when electrons tunnel between a barrier separating two superconductors. The effect indicated that the graphite samples contained superconducting areas.

Graphite, along with other materials, has held out the promise of room-temperature superconductivity before. For years there have been reports of weak, indirect superconducting signals coming from graphite coating treated with elements such as sulfur and oxygen. But nobody has been able to produce a definite room-temperature superconductor, a material that meets the definition of superconductivity, the conduction of electricity with zero resistance.

There are, however, other characteristics that mark a superconductor. A material typically becomes superconductive when it passes a temperature threshold and undergoes a distinct phase transition. The Josephson effect is another sign of superconductivity, and there is also the Meissner effect, also known as diamagnetism. When exposed to an external magnetic field, a superconductor pushes that field away so it doesn’t penetrate the material. The magnetic field inside the superconductor will be less than the field outside. This effect makes it possible for superconductors to levitate, and it also creates detectable changes in the external magnetic field, providing a measurable sign of superconductivity.

The physicists tested their treated graphite powder for diamagnetism by measuring its magnetization as it was exposed to a changing magnetic field. And it responded as if a fraction of the sample was indeed superconducting, but only a tiny fraction of 0.01 percent.

This is hardly an impressive portion. The amount is so teeny that it’s extremely difficult to characterize. But the notion that anything can be superconductive at room temperature, especially a substance as cheap and easily fabricated as flake graphite and water, would be a major discovery.