Complex ac permeability and harmonic generation of a thin film of YBa2Cu3O7-δ: Measurements and models

ac permeability and harmonic-generation measurements have been carried out on a pulsed-laser-deposited YBa₂Cu₃O_7-δ thin-film sample. The dependence of the inductive and dissipative components of the permeability on the ac magnetic-field amplitude indicates the absence of intergranular weak links in the sample, in contrast to results from bulk ceramic samples. Both the ac permeability and the harmonic spectra of the sample are well explained in terms of the critical-state model of Bean, which assumes that the critical current is independent of the magnetic field.