See also Absence of high temperature superconductivity in hydrides under pressure

About the Pressure-Induced Superconducting State of Europium Metal at Low Temperatures

Earlier versions: arXiv:2012.07537v1 (2020), Physica C 583, 1353805 (2021)
Last version: arXiv:2012.07537v3 (2021)

In Phys. Rev. Lett. 102, 197002 (2009) it was reported that Eu becomes superconducting in the pressure and temperature range [84-142GPa], [1.8-2.75K]. The claim was largely based on ac susceptibility measurements. Recently reported ac susceptibility measurements on a hydride compound that appears to become superconducting near room temperature (Nature 586, 373 (2020) ) cast serious doubt on the validity of the results for Eu as well as for the hydride. Here I present results that shed new light on the true behaviour of Eu. It is argued that the experiments on Eu should be repeated to validate or rule out the claim of superconductivity.