STUDIES OF OXIDES OF THE SYSTEM YBA2(CU1-XFEX)3O7-DELTA IN STRONG MAGNETIC-FIELD

Magnetic and superconducting properties of YBa2(Cu1-xFex)3O7-delta (0 less-than-or-equal-to less-than-or-equal-to x less-than-or-equal-to 0.12) are studied over the temperature range of 4.2-100 K. The temperature dependence of susceptibility in permanent magnetic field up to 130 kOe and field dependence of magnetization recorded in pulsed fields up to 250 kOe are used for evaluation of the second critical field and determination of the critical current density. It is found that the irreversible part of magnetization for compositions with x greater-than-or-equal-to 0.06 does not change with the iron content increase.