  By a systematic study of the hydrogen-doped LaFeAsO system by means of dc
resistivity, dc magnetometry, and muon-spin spectroscopy we addressed the
question of universality of the phase diagram of rare-earth-1111 pnictides. In
many respects, the behaviour of LaFeAsO_(1-x)H_(x) resembles that of its widely
studied F-doped counterpart, with H^- realizing a similar (or better)
electron-doping in the LaO planes. In a x = 0.01 sample we found a long-range
SDW order with T_n = 119 K, while at x = 0.05 the SDW establishes only at 38 K
and, below T_c = 10 K, it coexists at a nanoscopic scale with bulk
superconductivity. Unlike the abrupt M-SC transition found in the parent
La-1111 compound, the presence a crossover region makes the H-doped system
qualitatively similar to other Sm-, Ce-, or Nd-1111 families.
