Hydrogen migration in electron irradiated Pd based dilute alloys around the 50 K anomaly

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

“…Similar investigations were done for 12 C ion irradiated Pd-H specimens and electron irradiated Pd-1 at.% Fe and Pd-1 at.% Ag specimens in which the disordered hydrogen atoms were obtained by irradiation and the resistivity was measured at the temperatures during heating [6,7]. In the irradiated case a new additional substage was also observed for the alloys.…”

“…The overshooting of the recovery curves has not been observed even for the low heating rates in the previous irradiation case [7] of Pd-Fe or -Ag alloys. This may be caused by low hydrogen concentration and/or high number density of the ordered domains because the amount of charged hydrogen is low, generally, in the alloys and the ordered domains may form around impurities.…”

“…The reason for the difference from the results of Vajda et al was pointed out in previous papers [7,8], i.e. their order of reaction was obtained by an incorrect method.…”

“…for these heating rates the cooling rate of 0.098 K/min is not sufficiently low to complete the ordering as mentioned before. Therefore, the same heating-up procedure as after fast cooling (9.8 K/min) was done for the specimens, which are cooled down with the rate of 0.098 K/min as in the previous cases [6,7]. The difference between both curves at the same heating rate reflects the resistivity change due to the ordering.…”

“…In the present experiments, we have to do similar annealing procedures for the specimens, which were not only fast cooled down but were also slowly cooled down, to obtain the migration energies of the hydrogen as before [6,7]. The amount of hydrogen held in the disordered state by the fast cooling for each specimen is almost the same for each fast cooling as shown in Figs.…”