No matter how good a material is at conducting electricity, there's usually some resistance – unless you use superconductive materials. Since they can conduct electricity with absolutely no loss, they could be revolutionary if not for one little problem: they only work if kept extremely cold. But now researchers at Max Planck have reported a new record high temperature for superconductivity, at a toasty -23° C (-9.4° F).
Normally, when electrons are flowing through a conductor their negative charge means they repel each other, sending them bouncing off nearby atoms. That in turn wastes a decent chunk of their energy, and we can feel this unwanted side effect as the heat given off by electronic devices.
But that doesn't alway have to be the case. Superconductors keep electrons flowing with no resistance at all, which can go a long way towards improving electrical circuits and storage – for example, a loop of superconducting wire can keep an electrical current flowing indefinitely, with no need for a power source.
Unfortunately, for now superconductors need to be chilled to extremely low temperatures to work – usually below -234º C (-389º F), which all but rules them out for most practical uses. Ideally they would work at room temperature, but the best attempts so far have only gotten them to -70° C (-94° F).
The new study, by the same researchers as the previous record, has now managed to warm superconductors up to -23° C, which is a huge leap towards room temperature. To do so, the team placed metallic lanthanum and hydrogen gas into a pressure chamber and squeezed the samples intensely – up to 1.7 million times stronger than regular atmospheric pressure. That creates a material called lanthanum hydride (LaH10).
Next, the researchers cooled the material down, and found that at the relatively high temperature of -23° C, the electrical resistance dropped to zero. This finding was backed up by measurements taken in an external magnetic field.
"Our study is a major step and milestone on the road to superconductivity at room temperature," says Eremets, lead researcher on the study.
The next steps for the team are to experiment with other materials such as yttrium hydride, which may allow superconductivity at even higher temperatures.
The research was published in the journal Nature.
Source: Max Planck
