Lm. Fisher et al., SUPERPOSITION OF CURRENTS IN HARD SUPERCONDUCTORS PLACED INTO CROSSEDAC AND DC MAGNETIC-FIELDS, Solid state communications, 97(10), 1996, pp. 833-836
The superposition of currents in YBCO melt-textured samples placed int
o crossed ac and de magnetic fields is predicted and observed. This su
perposition is a direct consequence of the critical state model. The d
e magnetic field distribution is shown to become uniform wherever the
ac field has penetrated. Owing to this nonlinear process, the area of
the dc magnetization loop diminishes and eventually disappears complet
ely with an increase of the ac field magnitude. This means that under
the action of the external ac field, the static magnetic properties of
hard superconductors change and tend to the well known properties of
soft ones.