Direct identification of extended defects as vortex pinning centers in melt textured YBa2Cu3O7-Y2BaCuO5 composites

Single domain YBa2Cu3O7-Y2BaCuO5 melt textured ceramic composites have revealed a very rich microstructure, which has usually impeded, by using standard measurements, to evaluate the contribution of each defect to the enhancement of the critical current. We have measured the inplane magnetoresistance anisotropy and the anisotropic in-plane inductive critical currents and we show that together with the microstructural TEM analysis, the contribution of the different extended pinning centers can be separated. These results have allowed us to infer the kind of microstructure modifications required to improve the critical current. In particular, we present an isostatic pressing deformation technique as a very promising post-processing treatment to strongly increase the critical currents of these composites.Peer Reviewe

Nanoindentation of multilayered epitaxial YBa2Cu 3O7-d thin films and coated conductors

Nanoindenter tests were carried out on YBa2Cu3O7-δ (YBCO) coatings with different buffer layers, in order to obtain the Hardness (H) tendency, Young's modulus (E), and the fracture mechanism activated during the indentation process. Different pop-ins were observed in the load–displacement curves, and correlated with their residual nanoindentation imprints visualized by Atomic Force Microscopy. A trench was made by Focused Ion Beam in order to better understand the plastic behaviour activated under the residual imprint at 650 mN of applied load. During the first steps of nanoindentation experiments an elastic regimen takes place and the Hertzian equations can be applied to obtain the E for each YBCO coating. All YBCO coatings present similar E values and H tendencies. However, the YBCO/CeO2/Yttrium Stabilized Zirconia system exhibits a better mechanical stability probably due to the absence of microcracks under the indentation. In addition, an experimental process using nanoindentation technique is obtained in order to isolate the kind of buffer layer employed (single crystal substrate or metallic substrate).Peer Reviewe

Direct identification of extended defects as vortex pinning centers in melt textured YBa2Cu3O7-Y2BaCuO5 composites

Single domain YBa2Cu3O7-Y2BaCuO5 melt textured ceramic composites have revealed a very rich microstructure, which has usually impeded, by using standard measurements, to evaluate the contribution of each defect to the enhancement of the critical current. We have measured the inplane magnetoresistance anisotropy and the anisotropic in-plane inductive critical currents and we show that together with the microstructural TEM analysis, the contribution of the different extended pinning centers can be separated. These results have allowed us to infer the kind of microstructure modifications required to improve the critical current. In particular, we present an isostatic pressing deformation technique as a very promising post-processing treatment to strongly increase the critical currents of these composites.Peer Reviewe

Nanoindentation of multilayered epitaxial YBa2Cu 3O7-d thin films and coated conductors

Nanoindenter tests were carried out on YBa2Cu3O7-δ (YBCO) coatings with different buffer layers, in order to obtain the Hardness (H) tendency, Young's modulus (E), and the fracture mechanism activated during the indentation process. Different pop-ins were observed in the load–displacement curves, and correlated with their residual nanoindentation imprints visualized by Atomic Force Microscopy. A trench was made by Focused Ion Beam in order to better understand the plastic behaviour activated under the residual imprint at 650 mN of applied load. During the first steps of nanoindentation experiments an elastic regimen takes place and the Hertzian equations can be applied to obtain the E for each YBCO coating. All YBCO coatings present similar E values and H tendencies. However, the YBCO/CeO2/Yttrium Stabilized Zirconia system exhibits a better mechanical stability probably due to the absence of microcracks under the indentation. In addition, an experimental process using nanoindentation technique is obtained in order to isolate the kind of buffer layer employed (single crystal substrate or metallic substrate).Peer Reviewe

Direct identification of extended defects as vortex pinning centers in melt textured YBa/sub 2/Cu/sub 3/O/sub 7/-Y/sub 2/BaCuO/sub 5/ composites

Single domain YBa/sub 2/Cu/sub 3/O/sub 7/-Y/sub 2/BaCuO/sub 5/ melt textured ceramic composites have revealed a very rich microstructure, which has usually impeded, by using standard measurements, to evaluate the contribution of each defect to the enhancement of the critical current. We have measured the in-plane magnetoresistance anisotropy and the anisotropic in-plane inductive critical currents and we show that together with the microstructural TEM analysis, the contribution of the different extended pinning centers can be separated. These results have allowed us to infer the kind of microstructure modifications required to improve the critical current. In particular, we present an isostatic pressing deformation technique as a very promising post-processing treatment to strongly increase the critical currents of these compositesPeer Reviewe

Two Examples of Efficient Superconducting Cable Applications

Within the scope of the Supercable project granted by ENDESA, we have study some possible applications of the superconducting cable on linking of sub-stations. One of them considers the possibility to link two sub-stations at the medium voltage level (25 kV) by both, a standard set of copper cables and their equivalent superconducting cable. The second case establishes a comparison between a medium voltage superconducting link and the high voltage, 220= kV, counterpart. As in the first case, the energy and emissions savings are clearly coming from the lower impedance of the SC cable, in the second case the benefit is clearly due to the absence of transformers. Although superconducting cable benefits are not only related with efficiency or environmental impact, the higher efficiency could be an added value when considering a SC cable installation

Two Examples of Efficient Superconducting Cable Applications

Within the scope of the Supercable project granted by ENDESA, we have study some possible applications of the superconducting cable on linking of sub-stations. One of them considers the possibility to link two sub-stations at the medium voltage level (25 kV) by both, a standard set of copper cables and their equivalent superconducting cable. The second case establishes a comparison between a medium voltage superconducting link and the high voltage, 220= kV, counterpart. As in the first case, the energy and emissions savings are clearly coming from the lower impedance of the SC cable, in the second case the benefit is clearly due to the absence of transformers. Although superconducting cable benefits are not only related with efficiency or environmental impact, the higher efficiency could be an added value when considering a SC cable installation.Postprint (author’s final draft

Direct identification of extended defects as vortex pinning centers in melt textured YBa/sub 2/Cu/sub 3/O/sub 7/-Y/sub 2/BaCuO/sub 5/ composites

Single domain YBa/sub 2/Cu/sub 3/O/sub 7/-Y/sub 2/BaCuO/sub 5/ melt textured ceramic composites have revealed a very rich microstructure, which has usually impeded, by using standard measurements, to evaluate the contribution of each defect to the enhancement of the critical current. We have measured the in-plane magnetoresistance anisotropy and the anisotropic in-plane inductive critical currents and we show that together with the microstructural TEM analysis, the contribution of the different extended pinning centers can be separated. These results have allowed us to infer the kind of microstructure modifications required to improve the critical current. In particular, we present an isostatic pressing deformation technique as a very promising post-processing treatment to strongly increase the critical currents of these compositesPeer Reviewe

Two Examples of Efficient Superconducting Cable Applications

Within the scope of the Supercable project granted by ENDESA, we have study some possible applications of the superconducting cable on linking of sub-stations. One of them considers the possibility to link two sub-stations at the medium voltage level (25 kV) by both, a standard set of copper cables and their equivalent superconducting cable. The second case establishes a comparison between a medium voltage superconducting link and the high voltage, 220= kV, counterpart. As in the first case, the energy and emissions savings are clearly coming from the lower impedance of the SC cable, in the second case the benefit is clearly due to the absence of transformers. Although superconducting cable benefits are not only related with efficiency or environmental impact, the higher efficiency could be an added value when considering a SC cable installation

Epitaxial BaZrO3 tracks by electrospinning of metalorganic fibers on single crystals

Postprint (published version