Effect of annealing high-dose heavy-ion irradiated high-temperature superconductor wires

Abstract

Heavy-ion irradiation of high-temperature superconducting thin films has long been known to generate damage tracks of amorphized material that are of close-to-ideal dimension to effectively contribute to pinning of magnetic flux lines and thereby enhance the in-field critical current. At the same time, though, the presence of these tracks reduces the superconducting volume fraction available to transport current while the irradiation process itself generates oxygen depletion and disorder in the remaining superconducting material. We have irradiated commercially available superconducting coated conductors consisting of a thick film of (Y,Dy)Ba2Cu3O7 deposited on a buffered metal tape substrate in a continuous reel-to-reel process. Irradiation to emphasize the detrimental effects. The critical current was reduced following this irradiation, but annealing at relatively low temperatures of 200°C and 400°C substantially restore the critical current of the irradiated material. At high fields and high temperatures there is a net benefit of critical current compared to the untreated material.

Effect of doping on evolution of He⁺ion irradiation defects and superconductivity in EuBa₂Cu₃O_7–δ superconducting strips

“…学者们也开展了质子 [12,20] 、重离子 [21,22] 对REBCO带材的辐照效应研究, 证明低剂量离 子辐照能够提高超导体中微结构缺陷密度, 有效地 增加多种维度的磁通钉扎中心, 从而改善其超导性 能; 但过量辐照则导致超导正交相向非超导四方相 的相变、非晶无序化等现象, 使得T c 和J c 大幅降 低、超导电性严重损失. 同时有研究报道, 对中子 或重离子辐照的REBCO带材进行高温氧气退火 处理, 可以消除部分辐照缺陷, 恢复带材的超导电 性 [22][23][24] .…”

“…Unterrainer等 [23] 报道了中子辐照REBCO带材 通过氧气退火后, 带材的T c 随退火温度提高而 线性恢复, J c 也有所提升, 这归因于退火后超导层 超流体密度的恢复. Strickland等 [24] 报道了经过 185 MeV的Au离子高剂量辐照的REBCO带材,…”

Dynamic behavior of reversible oxygen migration in irradiated-annealed high temperature superconducting wires

“…By optimizing the parameters of chemical synthesis and particle irradiation, the depression can be controlled. On the other hand, annealing processes can lead to a recovery of T c 14 – 16 . The amorphous columnar defects remain stable, whereas oxygen disorders and point defects, restored by post-annealing, contribute to the improvement of film quality and superconductivity properties.…”

Characterization of the effect of ion irradiation on industrially produced GdBa2Cu3O7−δ superconducting tapes using a slow positron beam

“…[4][5][6][7][8][9][10][11][12][13][14] Previous studies on enhancing the critical-current characteristics of REBCOs using ion irradiation have been conducted mainly by forming columnar defects using highenergy (> 100 MeV) heavy-ion irradiation. [4][5][6][7][8][9][10] However, enhancement of the critical-current characteristics also has been reported by irradiation with electrons, 15) neutrons, 16,17) protons, 11) or relatively low-energy (< 20 MeV) ions 12,13) that do not form columnar defects. This suggests that small defects, which are not visible even with a transmission electron microscope (TEM), contribute to the enhancement.…”