Superconductivity in Hydrogen-Charged Ion-Beam Mixed Palladium Copper Alloy

Superconducting PdxCu1-x(H) has been made by ion-beam mixing and low-temperature electrolysis. A multi-layered sample consisting of alternate layers of Cu and Pd, sputter-deposited onto a Pd foil substrate, was bombarded with 125 KeV Xe+ ions. Analysis by Rutherford backscattering (RBS) showed the formation of a Pd.6Cu.4 alloy region approximately 38 micrograms/sq cm thick. After electrolytic charging with H at dry ice temperature, superconductivity was observed, with a transition temperature, Tc, of 11.4 K in the alloy region. The effects of increased currents and changes in the H distribution due to annealing between 77 k and 85 C on the transition curves have been investigated. Transition curves produced in this fashion are broad with an onset of the superconducting transition as high as 14 K. The sample remains partially superconducting even after overnight anneal at room temperature. Electrolysis at room temperature also produces superconducting transitions with onsets as high as 17 K.