60-Hz ac losses in Ag-doped high-temperature superconductors

60-Hz ac losses P were measured at temperature 77 K for sintered powder (YBa2Cu3O7)1-xAgx samples as a function of applied magnetic field h. Rod-shaped samples were cut from pellets for x = 0 and 0.05. The losses were measured in a uniform ac magnetic field h applied parallel to the sample surface. Measurements were made in fields up to h = 1000 A/cm rms at temperature 4.2 K and up to h = 600 A/cm rms at temperature 77 K. The results may indicate an increase of the intergranular current density and are discussed in relation to the grain size.