Research of YBCO Superconductor Coating on Austenitic Stainless Steel by Electrophoretic Deposition Method

Yttrium-based superconductors (YBCO) haven’t been widely applied. One reason is because of its high cost. In this study, we replaced the substrate and the fabrication method with lower-cost one, and found the possibility of making high-performance superconducting wires. Specifically, YBCO layer was fabricated by Electrophoretic deposition (EPD). Fabrication by this method needs calcination. The phenomenon that Fe in the substrate diffuses to YBCO layer during calcinating was confirmed. It was caused a decrease in YBCO performance. Therefore, CeO2 as an intermediate layer of substrate and YBCO was fabricated by EPD. It showed the possibility of preventing the spread of Fe. On the other hand, textured CeO2 layer was also fabricated in order to increase the characteristics of superconductor by EPD. And then it was also shown that to obtain a priority orientation is possible by controlling the current value.

Estimation of Self-Injection Length in Heterostructures of YBa2Cu3O7-δ Superconductor and La0.67Ca0.33MnO3 Manganite

Epitaxial bilayers of YBa2Cu3O7-δ (YBCO) and La0.67Ca0.33MnO3 (LCMO) heterostructures have been prepared by pulsed laser deposition technique, the growth sequence being YBCO on LCMO. The length scale of the YBCO layer, which is rendered non-superconductor/insulator by selfinjection of the spin polarized quasiparticles, is estimated to be 850Å. This can be an important guiding parameter in spintronic device configuration/fabrication.

Solution-processed lanthanum zirconium oxide as a barrier layer for high Ic-coated conductors

High-quality lanthanum zirconium oxide (La2Zr2O7 or LZO) films have been deposited and processed on Ni–W substrates using a sol-gel processing approach. It has been demonstrated that crack-free coatings with thicknesses up to 100 nm can be processed in a single step, while thicker coatings (200–225 nm) were processed using a multiple coating and annealing process. Using simulated metalorganic deposition (MOD)-YBa2Cu3O7−δ (YBCO) processing conditions, the barrier properties of the sol-gel LZO coating with a thickness of 120 nm were found to be comparable to that of the standard 3-layer buffer stack deposited using physical vapor deposition. Secondary ion mass spectroscopy depth profile analysis of LZO films annealed in oxygen-18 shows that LZO effectively stops the diffusion of Ni within the first 80–100 nm. Using MOD processes, a CeO2 cap layer and superconducting YBCO layer were deposited on sol-gel LZO/Ni–W. For the first time, using such an all-solution conductor architecture, a critical current (Ic) of 140 A/cm with a corresponding critical current density (Jc) of 1.75 MA/cm2 has been demonstrated. Using a very thin Y2O3 seed layer (∼10 nm) deposited by electron beam evaporation; improved texture quality in the LZO layers has been demonstrated. The performance of the LZO deposited on these samples was evaluated using a sputtered CeO2 cap layer and MOD YBCO layer. Critical currents of up to 255 A/cm (3.2 MA/cm2) with 0.8-μm-thick YBCO films have been demonstrated, comparable to the performance of films grown using physical vapor deposited yttria stabilized zirconia as a barrier layer. Similar experiments using an MOD-CeO2 cap layer and MOD-YBCO layer yielded critical currents of 200 A/cm (2.5 MA/cm2) with 0.8-μm-thick YBCO films.