Extrinsic conducting and superconducting polymer systems. IV. Superconducting properties of YBaCuO composites based on PVDF/PS/carbon black and PVDF/PS/copper polymer systems

✍ Scribed by C. Del Río; J. L. Acosta

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 542 KB
• Volume: 60
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/(sici)1097-4628(19960418)60:3<399::aid-app13>3.0.co;2-z

✦ Synopsis

In this work, the critical temperature (T,) of a series of polymeric superconducting systems is determined which, sintered or not, are obtained through the incorporation of the superconducting ceramic YBaCuO into two extrinsic conducting polymer systems: PVDF/PS/ carbon black and PVDF/PS/copper. In addition, the diamagnetic characteristics of these systems are studied on the basis of susceptibility measurements as a function of temperature. As regards the unsintered systems and according to the experimental results, copper-based composites can be termed as insulating materials and the samples with the highest carbon black content as reaching metalliclike conductivities. In no case, however, is a n abrupt leap in conductivity observed as a function of temperature, indicating the superconducting nature of these systems from an electrical point of view. On the contrary, magnetic susceptibility measurements as a function of temperature detect in all cases a superconducting transition, i.e., a shift in the critical temperature range, bringing it close to that of pure YBaCuO (-100 K). After sintering, the samples retained their original shape as well as reasonable mechanical properties. The electrical conductivity study confirmed the absence of superconductivity as a consequence of polymer combustion during sintering and thereby implying the disappearance of the orthorhombic phase of YBaCuO, which X-ray evidence proved to be accountable for superconductivity in this ceramic material.