High-field magnetization of high-Tc REBa2Cu3O7 compounds

The magnetization of high- T c superconducting REBa 2 Cu 3 O 7 compounds, where RE is Y or one of the rare-earth elements Eu, Gd, Dy, Ho, Er or Yb, has been measured in fields up to 29 T. Though the precise analysis of the data is hampered by the incomplete penetration of the magnetic field due to the shielding-current effect of the superconductivity, the magnetism associated with the rare-earth ions can reasonably be interpreted by crystal-field effects. All of the samples investigated were confirmed to be superconducting at 4.2 K in fields as high as 29 T.