MU-SR STUDIES OF HYDROGEN-INDUCED MAGNETIC-ORDERING IN HIGH-TC SUPERCONDUCTOR MATERIALS

High-T(c) ceramics (YBa2Cu3O7, YBa2Cu4O8 and GdBa2Cu3O7) were charged with hydrogen and investigated by the muon spin rotation (muSR) techni que. We find that for hydrogen concentrations of [H]/cell greater-than -or-equal-to 1 magnetic ordering, probably of the Cu(II) atoms, develo ps. Comparison of the observed muSR frequencies with dipolar field cal culations suggests that the magnetic structure of the Cu(II) atoms in the three samples is the same as in the well known antiferromagnetic c ompound YBa2Cu3O6 and that the muon is bound either to chain oxygens o r to the apical oxygens depending on the availability of chain oxygen sites.