Magnetic-Field Dependence of the Reversible Axial-Strain Effect in Y-Ba-Cu-O Coated Conductors

Published

June 1, 2005

Author(s)

Najib Cheggour, John (Jack) W. Ekin, C. L. H. Thieme

Abstract

The critical-current density J_c of an yttrium-barium- copper-oxide (YBCO) coated conductor deposited on a biaxially-textured Ni-5at.%W substrate was measured at 76.5 K as a function of axial tensile strain ε and magnetic field i}B applied parallel to the YBCO (a,b) plane. Reversibility of J_c with strain was observed up to ε approximately equal} 0.6 % over the entire field range studied (from 0.05 to 16.5 T), which confirms the existence of an intrinsic strain effect in YBCO coated conductors. J_c vs. ε epends strongly on magnetic field. The decrease of J_c(ε) grows systematically with magnetic field above 2-3 T, and, unexpectedly, the reverse happens below 2 T as this decrease shrinks with increasing field. The pinning force density F_p = J_c × i}B scaled with field for all values of strain applied, which shows that F_p can be written as K(T,ε)b^p(1 – b)^q, where i}p and i}q are constants, K is a function of temperature and strain, b = B/B^*_c2 is the reduced magnetic field, and B^*_c2 is the effective upper critical field at which F_p(B) extrapolates to zero.

Citation

IEEE Transactions on Applied Superconductivity

Volume

15

Issue

2

Pub Type

Journals

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Keywords

Coated Conductors, critical current, pinning force, RABiTs, reversible strain effect, scaling, YBCO

Citation

Cheggour, N. , Ekin, J. and Thieme, C. (2005), Magnetic-Field Dependence of the Reversible Axial-Strain Effect in Y-Ba-Cu-O Coated Conductors, IEEE Transactions on Applied Superconductivity, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=31877 (Accessed December 13, 2024)