A COMPARATIVE-STUDY OF INTERGRANULAR PINNING STRENGTHS IN HIGH-TEMPERATURE SUPERCONDUCTORS

We compare the irreversibility lines deduced from ac susceptibility me asurements on Y-123, Bi- and Hg compounds obtained by various techniqu es (sintering, zone melting, magnetic field texturing). Field and freq uency dependences are studied. Including results from the literature, our analysis indicate that fabrication methods containing a melting pr ocess favour the creation of pinning sites with high activation energi es. Although weaker than in single crystals, an important anisotropy i s induced by texturing processes.