Superconductivity of Cu/CuOx interface formed by shock-wave pressure

• Cu/CuOx interface superconducting at ∼19.5 K was formed by shock-pressure technique.
• Dynamic magnetic susceptibility of the interface was studied.
• Glassy dynamics of the superconducting shielding currents was observed.
• The superconducting interface is instable under normal conditions.

A mixture of powdered Cu and CuO has been subjected to a shock-wave pressure of ≃≃350 kbar with following quenching of the vacuum-encapsulated product to ≈77≈77 K. The ac magnetic susceptibility measurements of the samples have revealed metastable superconductivity with Tc≈19.5Tc≈19.5 K, characterized by glassy dynamics of the shielding currents below TcTc. Comparison of the ac susceptibility and the dc magnetization measurements infers that the superconductivity arises within the granular interfacial layer formed between metallic Cu and its oxides due to the shock-wave treatment.