Influence of random point defects introduced by proton irradiation on the flux creep rates and magnetic field dependence of the critical current densityJ_cof co-evaporated GdBa₂Cu₃O_7−δcoated conductors

Abstract

We report the influence of random point defects introduced by 3 MeV proton irradiation (doses of 0.5×10 16 , 1×10 16 , 2×10 16 and 6×10 16 cm −2 ) on the vortex dynamics of co-evaporated 1.3 μm thick, GdBa 2 Cu 3 O 7−δ coated conductors. Our results indicate that the inclusion of additional random point defects reduces the low field and enhances the in-field critical current densities J c . The main in-field J c enhancement takes place below 40 K, which is in agreement with the expectations for pinning by random point defects. In addition, our data show a slight though clear increase in flux creep rates as a function of irradiation fluence. Maley analysis indicates that this increment can be associated with a reduction in the exponent μ characterizing the glassy behavior.

Effect of mixed pinning landscapes produced by 6 MeV oxygen irradiation on the resulting critical current densities Jc in 1.3 µm thick GdBa 2 Cu 3 O 7- d coated conductors grown by co-evaporation

“…Nanoparticles aligned at the c-axis are expected to assist correlated pinning usually present in thin films due to defects such as dislocations and twin boundaries [13]. The precipitates are typically spaced between ∼100 nm and 200 nm, which corresponds to an equivalent matching field < 0.2 T. This is in agreement with high J c values at low fields and poor in-field dependences [16]. The inclusion of defects by oxygen irradiation in pristine CCS was analyzed in ref.…”

“…Despite the remarkable advance in the synthesis of desirable microstructures obtained at laboratory scale research, pinning landscapes including a high density of strong and weak pinning centers are usually difficult at industrial scale. This limitation in the synthesis of CCs has been recently overcome by including pinning centers by irradiation [15,16,17,18]. Depending on the mass and energy of the ions and the properties of the superconducting material, irradiation enables the creation of defects with well-controlled density and topology such as points, clusters, or tracks [19].…”

“…Depending on the mass and energy of the ions and the properties of the superconducting material, irradiation enables the creation of defects with well-controlled density and topology such as points, clusters, or tracks [19]. The in-field dependence of J c at temperatures below 40 K has been improved by irradiation with protons in CCs grown by metal organic deposition MOD and co-evaporation [15,16]. Most recently, the feasibility to similarly improve the properties of CCs obtained by MOD in much shorter irradiation times using 3.5 MeV 16 O 3+ has been reported [17].…”

“…The in-field dependence of J c at temperatures below 40 K has been improved by irradiation with protons in CCs grown by metal organic deposition MOD and co-evaporation [15,16]. Most recently, the feasibility to similarly improve the properties of CCs obtained by MOD in much shorter irradiation times using 3.5 MeV 16 O 3+ has been reported [17].…”

The Quest for High Critical Current in Applied High-Temperature Superconductors

“…Irradiation of superconductors to induce tailored defects to raise their critical current has so far remained in the realm of fundamental research. Only recently has the potential for improving the performance of coated conductors through particle irradiation been recognized [44][45][46][47][48][49][50][51][52][53][54][55][56].…”