REBa2Cu3Oy (RE=Rare Earth, REBCO) superconducting tapes are being studied to narrow the tape width to reduce AC losses. Typically, mechanical cutting with a slitting blade and laser cutting are used. However, these methods are processed after the superconducting thin films have been deposited, so there is a risk of tens of micrometers or more damage to the superconducting layers during cutting. Therefore, it is not easy to reduce the separating distances between filaments, which are dead spaces, at the micrometer-level. We have carried out a new method to separate the superconducting films by forming metal stripes of a few µm-width on the substrate before the deposition of superconducting films, where the metallic region acts as an electrically barrier region. In this study, we formed the Zr-stripes with micrometer-level width and investigated their separation state. The Zr-stripe was formed using the photolithography technique and spattering method. The widths at half maximum of the formed Zr-stripes are approximately 4.8 and 2.9 µm. YBa2Cu3Ox (YBCO) was then deposited on these substrates by the pulsed laser deposition. Surface observation of both samples by scanning electron microscopy shows lattice-like precipitates above the SrTiO3 substrate, which may reflect the biaxial orientation of the YBCO. On the other hand, large crystal grains were formed around the Zr-stripe. From the results of the trapped magnetic field distribution by the scanning hall-probe microscope, the magnetic field strength of the metallic region appears to be low, and superconducting areas are separated. DC magnetization measurements by a Physical Property Measurement System showed that both samples were about 0.1 emu in self-field and 60 K, which is about 1/7 of the YBCO thin films without Zr-stripe. This confirms that it is magnetically separated by the Zr-stripe of a few µm-width. The current-carrying properties of the Zr-stripe region are also discussed.
This work was supported in part by the Joint Research Hub Program of NIMS and by JSPS Grants-in-Aid for Scientific Research JP22H2019 and JP22H02021.
Keywords: Superconducting tape, REBa2Cu3Oy, Zr-stripe