Category Archives: TechBlog

Universal lower limit on vortex creep in superconductors

Eley at al. propose the existence of a universal minimum realizable S ~ Gi1/2(T/Tc) (Tc is the superconducting transition temperature, and  Gi = (γ2/2)[(μ0kBTc)/(4πBc2(0)ξab3(0))]2 γ2Tc2λ4/ξ2, The Ginzburg number, parameterizes the scale of thermal fluctuations in a superconductor) that has been achieved in our films and few other materials, and is violated by none.

Eley, S., M. Miura, B. Maiorov, and L. Civale, Universal lower limit on vortex creep in superconductors. Nat Mater, 2017. 16(4): p. 409-413.

Ic performance of 2G conductors from various manufacturers

Kiyosumi Tsuchiya et al. from Tsukukuba compared performance of 2G conductors from Fujikura Ltd.; SuNAM Co. Ltd.; SuperOx Japan LLC; and SuperPower Inc..

Tsuchiya, K., A. Kikuchi, A. Terashima, K. Suzuki, K. Norimoto, M. Tawada, M. Masuzawa, N. Ohuchi, X. Wang, Y. Iijima, T. Takao, S. Fujita, M. Daibo, and Y. Iijima, Critical Current Characterization of Commercial REBCO Coated Conductors at 4.2 and 77 K. IEEE Transactions on Applied Superconductivity, 2017. 27(4): p. 1-5.

It was found that the high-current 4-mm-wide conductors evaluated have non-Cu Jc values of ∼1000A/mm2 at 4.2 K in an 18 T perpendicular field, and 5060A/mm2 at 77 K in a 3 T perpendicular field. The differences in the in-field transport currents at 4.2 K among the conductors from different manufacturers investigated in this study are much larger than the differences at 77 K.