Abstract
Using high-resolution superconducting quantum interference device magnetometry, the field-cooled magnetization of Bi-2212 ceramics with bulk transition temperatures between 62 and 93 K has been investigated from 0.5 mOe to 5 Oe. Upon diamagnetic backgrounds of different magnitude and temperature variation, for all materials a positive contribution to appears, which increases to a formally inverted Meissner effect at the lowest fields, =H. The temperature variations of the diamagnetic and inverted responses indicate a common effect of a thermally activated process on both signals.
- Received 7 February 1995
DOI:https://doi.org/10.1103/PhysRevB.52.1215
©1995 American Physical Society