Angular dependence of harmonic ac responses in textured (Bi,Pb)2Sr2Ca2Cu3Oy/Ag tapes

Abstract

A silver-sheathed (Bi,Pb)2Sr2Ca2Cu3Oy tape is studied in terms of harmonic ac susceptibilities χn = χ′n-iχ″n(n = 3, 5, 7) to reveal the angular dependence of its physical properties. When the screening method is used, the higher harmonic responses are directly related to the nonlinear E(J) relation of the sample. Therefore, the effect of the silver sheath on the higher harmonic susceptibilities can be neglected. We perform measurements of the harmonic susceptibilities as a function of applied magnetic field or the angle between the magnetic field and the tape plane at various temperatures. The measured data are scaled onto a single curve by using the three-dimensional scaling relation. The derived anisotropic parameter γ ranges from 5.1 to 5.6 at the measured temperature region, which is consistent with the values obtained from transport measurements of the same tape. Such a small γ-value is attributed to the misalignment of the grains in the tape.