  Numerical simulations of the hysteretic ac loss in a coated superconductor
with a more realistic version of architecture were performed via finite-element
technique in the presence of an oscillating magnetic field. The coated
superconductor was electromagnetically modeled by resorting to the quasistatic
approximation of a vector potential approach in conjunction with the nonlinear
descriptions of the superconducting layer and ferromagnetic substrate therein
by a power law model and the Langevin equation respectively. A diverse effect
of the ferromagnetic substrate on the hysteretic ac loss, depending on the
strength of the applied magnetic field, was displayed and its underlying cause
was identified. The dependence of the hysteretic ac loss on the applied
frequency is found to be related to a critical amplitude of the applied
magnetic field, and the eddy-current loss dissipated in the metal coatings
becomes prominent as the frequency augments merely at high applied magnetic
fields.
