高温超伝導膜の磁化曲線におけるユニバーサリティ

概要

論文の詳細を見る
We made magnetization measurements on superconducting YBCO and BSCCO films with high c-axis orientation and found a universal dependence of normalized magnetization hysteresis ΔM/ΔM0 on normalized magnetic field H/H0 along the c-axis, where ΔM0 is the magnitude of hysteresis ΔM at H=0 and He is the “irreversibility field.” This relation between ΔM/Δ M0 and H/H0 is excellently fitted by a single curve irrespective of temperatures and materials investigated. Except for H-H0, ΔM/Δ M0 decreases exponetially with H/H0, while in the vicinity of H0 the data deviates from the exponential dependence. On the basis of the flux creep model, we succeeded in interpreting the universality by employing a logarithmic dependence of the effective pinning potential on current J at high density, which was recently proposed by Zeldov et al., and a linear J dependence at low density formerly proposed by Anderson and Kim.
社団法人粉体粉末冶金協会の論文