Superconductivity at 20 K in yttrium metal at pressures exceeding 1 Mbar

In experiments in a diamond anvil cell, yttrium metal is found to display a superconducting transition temperature in the ac susceptibility which increases monotonically from 3.5 K at 30 GPa to 19.5 K at 115 GPa, where the transition onset lies at 20 K. This is the second highest value of Tc ever observed for an elemental superconductor. A fit to the Y data… (More)