Resistivity behavior in isothermal annealing of Pd–H(D) alloys around 50K

Cooling rate dependence of the resistivity increase during hydrogen (deuterium) ordering in Pd–H(D) and Pd–Fe–H(D) alloys

“…Because the resistivity decreases with the hydrogen ordering in a later stage of ordering, these results show that in these ranges of heating or cooling rates, the size of ordered domains are below the critical size which corresponds to the maximum resistivity [8,16].…”

“…It has been clarified in previous investigations [7,[10][11][12][13][14][15] with electrical resistivity and/or neutron scattering that the resistivity of their alloys increases by the structural ordering of the hydrogen (deuterium) atoms and decreases by the disordering. However, it should be also considered that the resistivity increase is limited in the early stage of the ordering [7,8,16].…”

Hydrogen migration in fast cooled Pd–H alloys around 50K

“…The direction of the change in height of the resistivity maximum upon heating rate is opposite, in some times, to that expected for heating curves after slow cooling (0.098 K/min) if the resistivity increases with hydrogen ordering and decreases with disordering. In fact, the resistivity increase due to the ordering and the decrease due to the disordering are limited only to the early stage of the ordering as mentioned before [9,14,[16][17][18]. At the later stage of ordering, the resistivity decreases passing through the maximum as shown in the isothermal annealing curves for long time annealing [14].…”

“…The resistivity increase in the early stage and the decrease in the disordering are caused by the nucleation and growth of ordered domains and by the shrinking (when the size of the domains is smaller than the critical size) and/or disappearance of the domains, respectively. The resistivity also decreases in the later stage of hydrogen ordering due to the growth of the ordered domains [9,14,17]. The resistivity changes by fast cooling of the specimens were fairly large comparing with the change by slow cooling.…”

“…It has been already clarified by extensive studies with electrical resistivity measurement and neutron scattering measurement that the resistivity of Pd-H(D) alloys increases in the early stage of hydrogen ordering and decreases due to the disordering [2,5,[9][10][11][12][13][14][15][16][17]. The resistivity increase in the early stage and the decrease in the disordering are caused by the nucleation and growth of ordered domains and by the shrinking (when the size of the domains is smaller than the critical size) and/or disappearance of the domains, respectively.…”