Effects of the Nd4Ba2Cu2Oy phase on texturing and properties of melt-textured NdBa2Cu3Oy

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.

Section: Spatial Variation Of Superconducting Propertiesmentioning

confidence: 99%

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

Sakai

et al. 2005

“…Some micro-cracks propagate along the c axis. It is well known that a homogeneous distribution of RE211 inclusion suppresses the nucleation and propagation of micro-cracks [14], which otherwise dramatically deteriorates the field-trapping ability of bulk superconductors [15]. Furthermore, the flux pinning of RE211 inclusion is dependent upon RE211 interfacial area per unit volume V f /d [16].…”

Section: Microstructure Variationmentioning

confidence: 99%

Single-grain growth, microstructure and superconducting properties of (Sm, Eu)123 superconductors with BaCuO_2 xaddition

Sakai

Zhou

et al. 2002

High quality (Sm 0.5 , Eu 0.5 )Ba 2 Cu 3 O 7−δ single domains were grown in air with BaCuO 2−x addition. It was found that a RE-Ba substitution (RE: Sm and Eu) could be effectively suppressed by a small addition of BaCuO 2−x . The 94 K superconductivity with sharp transition was obtained in the composition range of 0.16 ∼ 0.33 BaCuO 2−x and (Sm 0.5 , Eu 0.5 )Ba 2 Cu 3 O 7−δ in a molar ratio. At 77 K, a surface field of 0.8 T was trapped in a single-domain pellet of 3.2 cm diameter. A further addition of BaCuO 2−x deteriorated the microstructure and degraded the superconducting performance.

“…On the other hand, when the processing conditions are the same a higher RE211 concentration results in a higher density. This can be understood by the fact that RE211 particles can diminish microcracks [23].…”

Section: Influence Of Arpreamentioning

confidence: 99%

The development of melt-processed (Sm,Eu,Gd)Ba₂Cu₃O_7−δ single-domain superconductors for high field applications

Hu¹,

Sakai²,

Murakami³

et al. 2004

(Sm,Eu,Gd)Ba2Cu3O7−δ (RE123) single-domain superconductors were grown in 1% O2 in Ar with a modified hot-seeding melt process. Spatial superconducting variation and a local RE–Ba modulation were suppressed with the control of processing conditions. Pre-annealing at 960 °C for 10 h in Ar prior to melt growth was found to significantly lower the range of RE–Ba substitution and diminish the number of pores and microcracks. Excess BaCuO2−x was added to induce a Ba-enriched liquid and thereby hinder the nucleation of RE1+xBa2−xCu3O7−δ solid solution (RE123ss). The proper ratio of BaCuO2−x to RE123 was around (0.17–0.25):1. The optimal thermal schedule was a fast cooling with a rate of 2 °C h−1 for 10 h followed by a 100 h slow cooling of 0.15 °C h−1. A field of 1 T was trapped in a pellet of 35 mm diameter at 77 K and 2 T, which corresponded to the maximum external flux density of 3 T including the bias applied field.