The intrinsic strain effect on critical current under a magnetic field parallel to thecaxis for a MOCVD-YBCO-coated conductor
Year: 2008
Type: article
Abstract: A new experimental set-up was developed to evaluate the strain dependence of critical current ( I c (ε a )) for YBa 2 Cu 3 O 7−δ (YBCO)-coated conductors under a magnetic field in a variable temperature environment. In this paper, we report the first results on the effect of a magnetic field parallel to the c axis ( ) on I c (ε a ) up to 10 T at temperatures of 60–77 K. We found that the magnetic field affects I c (ε a ) in a different manner, depending on the field region. When the magnetic field increases from B = 0 T, normalized I c (ε a ) is first improved and the optimal situation is realized under the characteristic magnetic field of B p = 0.2 T at 77 K and B p = 0.4 T at 70 K, respectively. For higher magnetic field, I c (ε a ) degrades further with increasing strain. From the results of a fitting analysis, we confirmed that the strain at the peak of I c (ε a ) shifts to higher strain and reaches the maximum value at B p . The peak shift as a function of magnetic field found in the YBCO-coated conductors is in contrast with the I c (ε a ) behavior for conventional low temperature superconducting composites, in which all of the critical parameters are optimized when the intrinsic strain of the superconductor is zero. From the present result, we can conclude that the peak strain of the I c (ε a ) curve under a magnetic field is not determined only by the thermal residual strain of the YBCO film in the coated conductor. For the high field region, the curvature of the I c (ε a ) curve increases with increasing magnetic field and temperature. It results in a steep decrease in I c (ε a ) at high magnetic fields and temperatures.
Authors: M Sugano, T Nakamura, T Manabe, K Shikimachi, N Hirano, S Nagaya
Institutions: Kyoto University, Chubu Electric Power (Japan)
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W1972507299