Production of Sharp-Edged and Surface-Damaged Y2BaCuO5 by Ultrasound: Significant Improvement of Superconducting Performance of Infiltration Growth-Processed YBa2Cu3O7-δ Bulk Superconductors

Sugali Pavan Kumar Naik; Muralidhar Miryala; Michael Rudolf Koblischka; Anjela Koblischka-Veneva; Tetsuo Oka; Masato Murakami

doi:10.1021/acsomega.9b02816

Production of Sharp-Edged and Surface-Damaged Y₂BaCuO₅ by Ultrasound: Significant Improvement of Superconducting Performance of Infiltration Growth-Processed YBa₂Cu₃O_7-δ Bulk Superconductors

ACS Omega. 2020 Mar 17;5(12):6250-6259. doi: 10.1021/acsomega.9b02816. eCollection 2020 Mar 31.

Authors

Sugali Pavan Kumar Naik^{1

2}, Muralidhar Miryala¹, Michael Rudolf Koblischka¹, Anjela Koblischka-Veneva¹, Tetsuo Oka¹, Masato Murakami¹

Affiliations

¹ Superconducting Materials Laboratory, Graduate School of Science and Engineering, Shibaura Institute of Technology, 3-7-5, Toyosu, Koto-ku, Tokyo 135-8548, Japan.
² Electronics and Photonics Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Central 2, Umezono, Tsukuba, Ibaraki 305-8568, Japan.

Abstract

Growth and physical properties of bulk REBa₂Cu₃O_7-δ (REBCO) superconductors fabricated by the infiltration growth (IG) method strongly depend on the initial size and morphology of the RE₂BaCuO₅ (211) particles. The present work details the novel method we developed for producing sharp-edged and surface-damaged 211 particles to be added to the REBCO bulks. We employed high-energy ultrasonic irradiation for pretreating the 211 particles and fabricated high-performance bulk single-grain YBa₂Cu₃O_7-δ (YBCO) superconductors via the top-seeded IG process. Increasing the ultrasound irradiation power and time duration mechanically damaged the surface of the 211 particles, producing more fine and sharp edges. Systematic investigations of the microstructural properties of the final YBCO bulks indicated that the size and content of the 211 particles gradually decreased without any additional chemical doping. The effective grain refinement and improved interfacial defect densities enhanced the critical current density by a factor of two at 77 K and self-field as compared to a YBCO sample fabricated without any pretreatment. A maximum trapped field of 0.48 T at 77 K was obtained for a sample (20 mm diameter) with 211 particles treated for 60 min and 300 W ultrasound radiation. The effectiveness of the novel method is demonstrated by the superior performance of the YBCO bulk samples prepared as compared to bulk samples fabricated with the addition of Pt and CeO₂. This method is novel, cost effective, and very convenient, maintaining high sample homogeneity, and is free of chemical contaminants as compared to other methods which significantly affect the properties of all REBCO bulk products grown by sintering, melt growth, and IG methods.