  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
K. The ac magnetic susceptibility measurements of the samples have revealed
metastable superconductivity with Tc = 19.5 K, characterized by glassy dynamics
of the shielding currents below Tc . 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.
