Broad temperature study of RE-substitution effects on the in-field critical current behavior of REBCO superconducting tapes

Abstract

The critical current behavior of REBa 2 Cu 3 O 7−δ (REBCO, with RE=Yb, Y, Ho, Dy, Gd, Eu, GdYb, DyY, GdY, EuY, SmY, GdEu, GdSm) superconducting tapes has been systematically studied for the temperature range of 10-77 K, magnetic field range of 0-5 T and field orientation (angle between the field and tape) of 0°-180°. We report that the RE size dependencies of infield critical current density (J c ) at low temperatures (below 40 K) are significantly different from those at 77 K. In a magnetic field of 1-3 T applied at 77 K, the J c of REBCO films increases with the RE ionic radius (r). EuBCO film, with the largest r in this study, shows the highest J c at 77 K in a magnetic field above 1 T, while YbBCO film, with the smallest r, has the lowest J c at 77 K. At temperatures below 40 K, however, the trend of in-field J c as a function of r reverses. There are crossovers among the functions of critical current density versus temperature for various RE ions and mixes. RE mixed films such as GdYBCO, EuYBCO, SmYBCO and GdEuBCO exhibit enhanced self-field critical current densities correlating with effective low field random pinning due to their suitable ion size variance. Strongly enhanced pinning by both random and correlated defects has been obtained in GdYbBCO films. Those pinning centers are especially effective at low temperatures. In a magnetic field of 5 T applied at 10 K, GdYbBCO gives the highest critical current density compared with other REBCO films, being 1.9 times greater than GdEuBCO film. This work provides a guideline regarding how to optimize RE ions in REBCO films for given application temperatures and magnetic fields.

Development and large volume production of extremely high current density YBa2Cu3O7 superconducting wires for fusion

“…The doping pattern of fully oxygenated REBa 2 Cu 3 O 7-δ (δ ≈ 0) has been well studied, and low temperature anneals at high oxygen partial pressure are applied. Recently, Zhang et al 45 reported a systematic dependence of REBCO J c (B) on the RE 3+ radius, obtaining higher J c for the smaller radii. Although the authors did not attribute the effect to the hole doping level, our data comparing YBCO and GdBCO wires (Fig.…”

Comparison of the Microstructure and Superconducting Properties of Eu–Ba–Cu–O and Gd–Ba–Cu–O Single Grain Samples

“…In addition to the processing conditions (eg heat treatment steps) which considerably influence the microstructure of the REBCO bulks, the Rare Earth element also plays a key role in determining the growth rate and microstructure [2,3]. A number of rare earths including Nd, Sm, Eu, Gd, Dy and Y have been incorporated into (RE)BCO single grains, and the superconducting properties of the bulks carefully studied, and it is known that the final microstructure varies with the RE element [2][3][4]. This is because the peritectic temperature of REBCO and RE solubility in Ba-Cu-O melt vary for different Rare Earth elements leading to different growth conditions for the REBCO phase.…”

“…This is because the peritectic temperature of REBCO and RE solubility in Ba-Cu-O melt vary for different Rare Earth elements leading to different growth conditions for the REBCO phase. This could considerably influences the microstructures of the REBCO bulks and the final superconducting properties, including the trapped magnetic fields [4].…”

“…Among all the REBCO compounds, YBCO is one of the most widely studied, and the properties can be further improved by doping and the use of mixed rare earth elements. Studies also show that compared to YBCO, the compounds of GdBCO, EuBCO and SmBCO can have higher critical current density at 77 K under self-field conditions [4,5] which is highly beneficial for engineering applications. However, the growth process requires optimization for each rare earth element.…”

Combinatorial Screening of Cuprate Superconductors by Drop-On-Demand Inkjet Printing

“…8 Despite the good properties exhibited in some cases, the exploration of other RE is still scarce, sometimes limited by stability or synthesis complexity of some REBCO phases. The focus has been shifted in recent years to RE mixing such as Y/Gd, 6,9,10 Gd/ Yb, 11,12 Y/Sm, 13,14 and Dy/Gd, 15 aiming to overcome such predicaments, as well as to shed light on the right combination that enables best superconducting properties. The initial push of the superconductor industry has been made with several film deposition techniques to achieve epitaxial growth; mandatory to transport large electric currents through the material.…”