Magnetic hysteresis of the zero-resistance critical temperature in YBaCuO,BiSrCaCuO and HgBaCaCuO superconducting polycrystals

A comparative study of the hysteretical behavior of the zero resistance cri tical temperature for YBa2Cu3O7-delta (BiPb)(2)Sr2Ca2Cu3O10+delta and (HgRe )Ba2Ca2Cu3O8+delta superconducting ceramics was performed at low magnetic f ields (under 400 Oe). The results were compared with those obtained through the magnetic hysteresis of the critical current density, showing good agre ement in most cases. The qualitative explanation of the observed hysteresis in terms of intragranular flux trapping of the superconducting grains sati sfies YBaCuO and BiSrCaCuO materials, but modifications might be necessary in the case of HgBaCaCuO. (C) 1999 Published by Elsevier Science B.V. All r ights reserved.