INVESTIGATION OF THE DB/DH EFFECT USING TRAPPED FLUX IN TYPE-II SUPERCONDUCTORS

We show that the dB/dH effect (i.e., a ''discontinuity'' in the B profile) should manifest itself quite dramatically in plots of [B](rem)/[B](in) vs either [B](in) or vs [B](rem). Here [B](in) is the magnetic-flux density permeating the zero-held-cooled specimen in the presence of an applied magnetic field H-alpha and [B](rem) is the remanent magnetic-flux density after H-alpha has been removed. Our data on the five materials we have investigated (two weak pinning, two intermediate, and one strong pinning low-T-c type-II superconductors) graphed in these discriminating formats show no evidence of a dB/dH effect.