Influence of the surface melting of Y1Ba2Cu3O7 − δ polycrystalline samples on their resistivity and critical currents

✍ Scribed by S.R. Currás; G. Domarco; O. Cabeza; J.A. Veira; F. Vidal

• Publisher: Elsevier Science
• Year: 1997
• Tongue: English
• Weight: 469 KB
• Volume: 37
• Category: Article
• ISSN: 0011-2275
• DOI: 10.1016/s0011-2275(97)00048-9

✦ Synopsis

Measurements

of the electrical resistivity, p, and of the critical current, /,, of polycrystalline Y,Ba,Cu,O,_, samples before and after being melted superficially are presented. The melting was done by heating the samples at 1050°C during a few minutes, and then annealing at 900°C in flowing oxygen during several hours. This melting process may increase /, by up to two orders of magnitude, while p changes by a factor of three or less. Scanning electron microscopy (SEMI and optical microscopy with polarization of the cross-section of the sample suggests that in the melted surface a grain alignment (typically 50 pm to 100 em deep), similar to that observed in the whole volume in textured samples, appears. We relate such an important increase of 1, and the slight variations in p with differences of the spatial current density redistributions associated with these two quantities (in surface for 1, and in volume for p).