Superconductivity above 200 K discovered in superhydrides of calcium

Searching for superconductivity with T c near room temperature is of great interest both for fundamental science & many potential applications. Here we report the experimental discovery of superconductivity with maximum critical temperature (T-c) above 210 K in calcium superhydrides, the new alkali earth hydrides experimentally showing superconductivity above 200 K in addition to sulfur hydride & rare-earth hydride system. The materials are synthesized at the synergetic conditions of 160-190 GPa and similar to 2000 K using diamond anvil cell combined with in-situ laser heating technique. The superconductivity was studied through in-situ high pressure electric conductance measurements in an applied magnetic field for the sample quenched from high temperature while maintained at high pressures. The upper critical field Hc(0) was estimated to be similar to 268 T while the GL coherent length is similar to 11 angstrom. The in-situ synchrotron X-ray diffraction measurements suggest that the synthesized calcium hydrides are primarily composed of CaH6 while there may also exist other calcium hydrides with different hydrogen contents.

Automated summary

Researchers have discovered superconductivity in calcium superhydrides with a critical temperature above 210 K, which is of great interest for finding superconducting materials near room temperature. The study analyzed the material's superconductivity through high-pressure electric conductance measurements, estimating an upper critical field of 268 T and a GL coherent length of 11 angstrom.