Superconductivity of Al/Al2O3 interface formed by shock-wave pressure

• Al/Al2O3 interface superconducting at ∼37 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 Al and αα-Al2O3 has been subjected to a shock-wave pressure of ≃≃170 kbar, followed by vacuum-encapsulating and quenching of the product to liquid nitrogen. The ac magnetic susceptibility measurements of the samples have revealed metastable superconductivity with Tc≈37Tc≈37 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 interfacial granular layer formed between metallic Al and its oxide due to the shock-wave treatment.