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

Abstract

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.