Microstructures of REBa₂Cu₃O_y adding BaZrO₃ or BaSnO₃

BaZrO₃ nanorods have potential for use as artificial pinning centers when introduced into practical superconducting wire tapes due to their simple fabrication technique and effective pinning force. In the case of adding BaSnO₃ to REBa₂Cu₃O_y (RE: rare-earth element) films, BaSnO₃ nanorods are formed similar to the case of adding BaZrO₃. The structures of the BaZrO₃ nanorods in REBa₂Cu₃O_y films were usually confirmed by cross-sectional transmission electron microscopy (TEM). The BaZrO₃ nanorods were approximately perpendicular to the REBa₂Cu₃O_y films, but bent BaZrO₃ nanorods were sometimes observed in thicker films. Furthermore, it was difficult to understand the structure of high-density BaZrO₃ nanorods from cross-sectional TEM images due to their overlap. Therefore, we observed the microstructure of REBa₂Cu₃O_y films containing BaZrO₃ or BaSnO₃ nanorods by plan-view TEM to understand the structure of the nanorods.