Relations Between Superconducting Transition Temperatures and Corresponding Hydrogen Activities of Palladium Hydride Samples

摘要

One of the unexpected discoveries in palladium hydride is its superconductivity.It occurred during the search for low temperature electrical resistance anomaly in nickel hydride,in analogy to the previously known anomaly in palladium hydride.In fact,only an electrical resistance minimum was found in nickel hydride.Thus,the next logical step was the search for electrical resistance anomalies in hydrides of Pd-Ni alloys.It were these alloys and pure palladium,where superconductivity was found in 1972,as a result of electrochemical hydrogen charging.The very reason,that this happened in 1972 in Holland and not 4 years earlier in Poland was the lack of lower than liquid He temperatures(4.2 K)in Poland in that time(notice that all superconducting samples needed lower temperatures than 4.2 K!).