“High-Temperature Superconducting Phase in Clathrate Calcium Hydride CaH₆ up to 215 K at a Pressure of 172 GPa” (2022), by Ma, Liang et al. Earth and Planetary Sciences research paper. Original abstract below, unchanged. No free PDF was found.

High-Temperature Superconducting Phase in Clathrate Calcium Hydride CaH₆ up to 215 K at a Pressure of 172 GPa

Ma, Liang, Wang, Kui, Yu Xie et al. · January 1, 2022 · Earth and Planetary Sciences

Abstract

The recent discovery of superconductive rare earth and actinide superhydrides has ushered in a new era of superconductivity research at high pressures. This distinct type of clathrate metal hydrides was first proposed for alkaline-earth-metal hydride CaH₆ that, however, has long eluded experimental synthesis, impeding an understanding of pertinent physics. Here, we report successful synthesis of CaH₆ and its measured superconducting critical temperature T_c of 215 K at 172 GPa, which is evidenced by a sharp drop of resistivity to zero and a characteristic decrease of T_c under a magnetic field up to 9 T. An estimate based on the Werthamer-Helfand-Hohenberg model gives a giant zero-temperature upper critical magnetic field of 203 T. These remarkable benchmark superconducting properties place CaH₆ among the most outstanding high-T_c superhydrides, marking it as the hitherto only clathrate metal hydride outside the family of rare earth and actinide hydrides. This exceptional case raises great prospects of expanding the extraordinary class of high-T_c superhydrides to a broader variety of compounds that possess more diverse material features and physics characteristics.

Source page DOI: 10.3204/pubdb-2022-06634