Magnetic properties of milled and thermal relaxed YBa2(Cu1-xFex)(3)O-y

The influence of the mechanical milling and subsequent thermal relaxation on magnetic and superconducting behaviour of YBa2(Cu1-xFex)(3)O-y system has been studied. Two methods of heat treatment were used: Set I - slow cooling from 980 degrees C in flowing O-2 and Set II - reducing at 770 degrees C in flowing Art followed by reoxidation in flowing O-2 below 400 degrees C. The transition to superconductivity, diamagnetic response, critical current density and the effective magnetic moment in the normal state have been estimated. Our measurements indicate that the reducing atmosphere preparation is less detrimental on superconducting properties. The results are discussed in terms of occupancy Cu sites by Fe and redistribution of oxygen atoms.