Hydrogenation of thin Y-Ba-Cu-O films: Electrical transport and structure properties of YBa[sub 2]Cu[sub 3]O[sub 7] and YBa[sub 2]Cu[sub 4]O[sub 8]

[ital c]-axis-oriented YBa[sub 2]Cu[sub 3]O[sub 7] (1:2:3) and YBa[sub 2]Cu[sub 4]O[sub 8] (1:2:4) thin films were charged with hydrogen at 463 K and a H[sub 2] pressure of 100 mbar. The hydrogen concentrations and depth profiles were measured with the [sup 15]N nuclear reaction method. In contrast to earlier studies on bulk samples where a constant [ital T][sub [ital c],onset] is reported, we find in our 1:2:3 films that the superconducting transition temperature decreases continuously with increasing hydrogen concentration and that the transitions remain relatively sharp, e.g., [ital T][sub [ital c],onset]=38 K and [Delta][ital T][sub [ital c]]=6.2 K for [H]/cell[congruent]0.6. The electrical resistivity and Hall-effect measurements in the normal state indicate that the main effect of hydrogen doping is a reduction of the charge carrier concentration, whereas the carrier mobility is not changed significantly. At an average hydrogen concentration of [H]/cell[congruent]2 in both systems, a new hydride phase is observed, which for 1:2:3 is characterized by a [ital c]-axis expansion of 16% and for 1:2:4 by a [ital c]-axis expansion of 1.5%.