Resistivity maximums due to growth of hydrogen-ordered domains in resistivity curves of Pd-H alloys during heating up with constant rates

摘要

The resistivity maximum in the isothermal annealing curve of Pd-H(D) alloys is caused by the nucleation and growth of ordered domains of hydrogen (deuterium) atoms as reported in a previous paper; the resistivity increases in the early stage of hydrogen (deuterium) ordering and decreases in the later stage. In order to determine whether a similar decrease of electrical resistivity is present in the heating-up curves during hydrogen ordering, the resistivity of Pd-H alloys is investigated for various hydrogen concentrations and various constant heating-up rates. Two resistivity maximums, or one maximum and hump are observed in the curves at low heating-up rates, i.e. the resistivity decrease due to the ordering different from the decrease due to the disordering is clearly separated as the first maximum. The heating-up rates observed in the above separation depend on the hydrogen concentration.