Contactless measurement of voltage-current characteristics of high-Tc thin film superconductors

✍ Scribed by M. Polák; V. Windte; W. Schauer; J. Reiner; A. Gurevich; H. Wühl

• Publisher: Elsevier Science
• Year: 1991
• Tongue: English
• Weight: 584 KB
• Volume: 174
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/0921-4534(91)90415-u

✦ Synopsis

A contactless inductive method is proposed and tested to determine E(j) and jc(B) characteristics of ring shaped samples patterned from YBa2Cu307_x thin films. The method is based on monitoring the magnetic field B~ generated by a current in the high-To ring, which is induced by an external magnetic field sweep dB,/dt. The sample field B, is detected by a small area Hall sensor ( ~ 50/~m× 50~tm). The capability of the method is demonstrated for two 1 ~tm thick ring samples. Films were prepared by cylindrical magnetron sputtering and patterned photolithographically (mean ring diameter -~ 3.5 mm, ring width ~-0.5 mm). Magnetic field profiles along the ring diameter and hysteresis loops Bs (Be) are interpreted using Bean's model. A sensitivity limit of E-~ 5 × l0 -5 p.V/cm allows us to adopt E-criteria in j¢(B) measurements four orders of magnitude lower than in resistive experiments. An exponential E(j) relation is observed in an electric field interval of three decades.