<i>J</i><sub>c</sub> and composition distribution of YBCO coated conductors fabricated by the TFA-MOD process

Shuya Sakai, Yoshiki Tanaka, Ryo Teranishi, Masataka Iwakuma, Masayoshi Inoue

Research output: Contribution to journalArticlepeer-review

Abstract

The Trifluoroacetate-Metal Organic Deposition (TFA-MOD) process is one of the most promising fabrication processes for low-cost superconducting coated conductors (CCs) because of its high yield and non-vacuum system. However, in the doping and multi-coating process for the enhancement of critical current (<i>I</i><sub>c</sub>), degradation of <i>I</i><sub>c</sub> often occurs. In this study, to clarify the origin of <i>I</i><sub>c</sub> degradation, we have investigated the local critical current density (<i>J</i><sub>c</sub>) distribution, in-field <i>J</i><sub>c</sub> properties and the variation of composition for TFA-MOD processed YBa<sub>2</sub>Cu<sub>3</sub>O<sub>y</sub> (YBCO) CCs. The local <i>J</i><sub>c</sub> distributions were measured by Scanning Hall-Probe Microscopy for confirming the location of the high/low-<i>J</i><sub>c</sub> regions. The CCs were then cut into 3 mm3 mm or 3 mm4 mm for dc magnetization measurement. The <i>T</i><sub>c</sub> of the all samples were about 87 K to 90 K. In-field <i>J</i><sub>c</sub> at 77 K was obtained from M-H measurements and all the samples were compared with each other. The in-field <i>J</i><sub>c</sub> of high-<i>J</i><sub>c</sub> sample showed about 100 times higher value than that of the low-<i>J</i><sub>c</sub> sample. Then we have observed the microchemistry and the variation of composition by SEM-EDS. In the high-<i>J</i><sub>c</sub> sample, the grains of the superconducting phase were large in size and were connected to each other. This means that superconducting current could form through the whole sample area and generate a large magnetic moment. On the other hand, in the low-<i>J</i><sub>c</sub> sample, though the superconducting phase could be observed, the grains were small in size and sparse. Therefore, the magnetic moment measured was small. However, it was also suggested that the intra-grain <i>J</i><sub>c</sub> would be almost the same as that of high-<i>J</i><sub>c</sub> sample.

Original languageEnglish
JournalIEEE Transactions on Applied Superconductivity
DOIs
Publication statusAccepted/In press - 2022

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering

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