A new perspective to AC magnetic susceptibility measurements in an unbalanced mutual inductance bridge

AC magnetic susceptibility measurements using an unbalanced mutual inductan ce bridge were performed on a bulk YBa2CU3O7-delta superconductor at freque ncies f = 110-800 Hz and AC fields B = 0.2-2 mT. By deliberately leaving th e bridge unbalanced, the effect of phase drift on the measurements is shown . Because of this phase drift, we found that the hump appearing in the in-p hase measurements (associated with X') is the same AC loss peak appearing i n the out-of-phase measurements (associated with x "). In addition, since t he behavior of the AC susceptibility data we obtained is in agreement with the literature, conflicting results by other groups can be resolved by a si mple consideration of this phase drift. (C) 2001 Elsevier Science B.V. All rights reserved.