Magnetic susceptibility, Mössbauer spectroscopy, nuclear quadrupole resonance of Cu (NQR), nuclear magnetic resonance of Cu in the hyperfine field of the antiferromagnetic state (AFNMR), and x-ray diffraction measurements were performed to study the superconducting and magnetic properties of hydrogen charged bulk ${\mathrm{YBa}}_2$${\mathrm{Cu}}_4$${\mathrm{O}}_8$${\mathrm{H}}_{\mathit{y}}$. For y<1 the c lattice parameter decreases with y. In contrast to Fe-doped ${\mathrm{YBa}}_2$${\mathrm{Cu}}_3$${\mathrm{O}}_7$${\mathrm{H}}_{\mathit{y}}$, where ${\mathit{T}}_{\mathit{c}}$ decreases continuously with increasing y, we find here that for 1% Fe doped, ${\mathit{T}}_{\mathit{c}}$=59 K is unaffected by hydrogen charging, but the shielding fraction is reduced sharply from 38% for y=0 to 17% and 3% for y=1 and 1.85, respectively. The Mössbauer spectra for y=0 at T>90 K contain one doublet. The spectra for hydrogen charged samples, in addition to this doublet, contain a magnetic pattern composed of two sextets, between 4.1 K and ${\mathit{T}}_{\mathit{N}}$=360 K. The relative amount of the magnetic pattern depends on hydrogen concentration. The Mössbauer spectrum obtained for y=1 is a superposition of spectra obtained for y=0 and those for y=2, showing a phase separation into magnetic and superconducting regions in ${\mathrm{YBa}}_2$${\mathrm{Cu}}_4$${\mathrm{O}}_8$${\mathrm{H}}_{\mathit{y}}$. NQR-AFNMR studies of ${\mathrm{YBa}}_2$${\mathrm{Cu}}_4$${\mathrm{O}}_8$${\mathrm{H}}_{\mathit{y}}$ and ${\mathrm{GdBa}}_2$${\mathrm{Cu}}_4$${\mathrm{O}}_8$${\mathrm{H}}_{\mathit{y}}$ samples indicate that magnetic order is induced only in the Cu(2) planes.

• Received 1 July 1994

DOI:https://doi.org/10.1103/PhysRevB.50.15858