Effect of Gd₂Ba₄CuMoO_yaddition on the band structure and spatial variation of superconducting properties in GdBa₂Cu₃O_7−δsingle domains

Abstract

Gd2Ba4CuMoOy (Gd2411) single phase was synthesized in air and added into GdBa2Cu3O7−δ (Gd123) bulk superconductors with the addition amount ranging from 0.2% to 20%, in molar ratio to Gd123. Both microstructure and superconducting properties of each bulk were investigated from the seed position to the boundary of a single domain. Although a band structure with the alternative distribution of Gd2BaCuO5 (Gd211) and Gd2411 appeared in all samples, the range of this inhomogeneity only appeared within 5 mm from each side of the seed. The critical current density (Jc) shows that Gd2411 plays an important role in the control of the local superconducting properties. The highest Jc reached 84 500 A cm−2 at 77 K under the self-field in the sample with 0.4% addition of Gd2411.

High performance of air-processed GdBa2Cu3O7-δsuperconductors with fined Gd2BaCuO5and Gd2Ba4CuMoOxadditions

“…The second phase rich and diluted bands alternatively distributed and this kind of band structure appeared in all the bulks with Gd2411 addition in our study, even 0.002 Gd2411 [9]. But this kind of band structure only appears within 5 mm from each side of the seed.…”

Growth and properties of air-processed GdBa2Cu3O7−δ superconductors with fined Gd2BaCuO5 and Gd2Ba4CuFeOy additions

“…The mixed powders were pressed into pellets with 20 mm in diameter and 8 mm in thickness. The melting process of the bulk superconductors and the post-annealing in argon and oxygen gases have been reported elsewhere [2,8].…”

“…Recently, RE 2 Ba 4 CuMO y (M = Nb, Ta, Mo, W, Re, Zr and Hf) [7,8] as second phase with RE211 have successfully fabricated single grain RE123 bulk. It is observed that RE2411 inclusions can embed in the superconductor matrix in nano-size and form effective magnetic flux pinning sites to increase J C .…”

Comparative study of critical current density, pinning force and levitation force behavior in Yb211 doped-Sm123 bulk superconductors

“…In many research center, various kinds of chemical doping, including metal and nonmetal elements particles of magnetic alloys [13][14][15][16], various insulating particles such as RE 2 BaCuO 5 (RE211) and RE 2 Ba 4 CuO 5 (RE-2411) and other nonsuperconducting particle have been used as secondary phase particles which can be act as pinning centers in bulk HTS superconductors [17][18][19]. It is well known that, compared to YBa 2 Cu 3 O y−ı the (LRE)Ba 2 Cu 3 O 7−ı superconductors, where LRE is a light rare earth element, such as La, Nd, Sm, Eu and Gd, attract important attention as a consequence of their higher superconducting transition temperature (T c ) and critical current density (J c ), especially in medium and strong magnetic fields.…”