Physicists hit a major breakthrough by achieving superconductivity at the highest temperature ever recorded with a material called lanthanum superhydride.
Superconductivity At Room Temperature
Superconductivity, which is the ability of electrical current to flow freely with zero resistance, typically occurs at extremely low temperatures in most materials. Finding a material that could conduct electricity at room temperature — or at least as close to it as possible — is important since cooling is expensive and therefore limited in practical applications.
In a new paper published in the journal Nature, an international team of researchers recorded superconductivity at about minus 23 degrees Celsius (minus 9 degrees Fahrenheit), which is about 50 degrees higher than the previous record.
This isn't quite room temperature of greater than 0 degrees Celsius, but it's as near as anyone has ever gotten.
Lanthanum Hydride: A New Superconductor?
Recently, scientists have focused on a class of materials known as hydrides for high-temperature superconductivity. The new study, which was conducted by researchers from Max Planck Institute for Chemistry and University of Chicago, involves creating a substance called lanthanum hydride and testing its superconductivity.
Lanthanum hydride needs to be under extremely high pressure at about 150 to 170 gigapascals, which is over one and a half million times greater than sea level pressure.
To achieve this, the researchers placed a tiny sample of lanthanum between two diamonds in a box of pressurized hydrogen gas and squeezed until they reached the required pressure. Then they used lasers to form lanthanum hydride. Finally, measurements were taken to confirm the material's composition and superconductivity.
Study Findings
Incredibly, the material was discovered to exhibit three of the four characteristics of superconductivity, a report from the University of Chicago revealed. It had no electrical resistance, dropped critical temperature levels with an external magnetic field, and changed temperature when a number of elements were replaced with different isotopes.
The last indicator of superconductivity is the Meissner effect, in which a material doesn't allow magnetic fields to pass through. It hasn't been detected in lanthanum hydride, as the study authors say the sample was too small to observe the phenomenon.
"Our next goal is to reduce the pressure needed to synthesize samples, to bring the critical temperature closer to ambient, and perhaps even create samples that could be synthesized at high pressures, but still superconduct at normal pressures," said study co-author Vitali Prakapenka of the University of Chicago. "We are continuing to search for new and interesting compounds that will bring us new, and often unexpected, discoveries."
