Magnetic properties of YBa2Cu3O7-delta melt textured samples prepared by powder melting process and quench and melt growth techniques

The microstructure and magnetic properties of the melt textured YBa(2)Cu(3) o(7-delta) samples prepared by the powder melting process, in which Y2Cu2O5 and BaCuO2 were used as precursors, and those prepared by the quench and m elt growth method are described and compared. The lattice parameters and T- c values for the samples prepared by the both techniques were similar. The penetration and the spatial distribution of the magnetic flux in the superc onducting samples was imaged by means of a field-mapping device using a Hal l probe. In the range of low magnetic fields up to 820 A m(-1) no significa nt differences in penetration of magnetic flux between the samples prepared by the powder melting process and the quench and melt growth were observed . The mapping could not resolve any grain boundaries, single grains and str uctural defects. By the ac and virgin volume magnetisation characteristics, which were measured in the zero-field cooled condition by a 2nd order SQUI D gradiometer, no weak links were identified. Better magnetic properties of the quench and melt growth samples in high magnetic fields can be explaine d by the differences in microstructure and/or by the risen content of the f inely dispersed 211 and Pt containing phases. The increase factor in magnet isation is about 2.5. Some aspects of the Bean model for textured YBa2Cu3O7 -delta samples are discussed.