In this study we prepared Y_xYb_1-xBa₂Cu₃O_7-σ (x=0, 0.1, 0.2, 0.3, 0.4, 0.5, 1) bulks for superconducting joint between REBCO-coated conductors. The fabrication method for the joint is crystalline joint by a melted bulk (CJMB) [1]. The joint is useful in developing high-field REBCO persistent magnets. During the heat treatment, all the samples were prepared at 1123 K for 10 hours in air. The XRD patterns of the samples were shown in Figure 1. As seen in Figure 1, the arrows indicated a gradual change in peak intensity with increasing of x value. These bulks will be used to develop a superconducting joint between REBCO-coated conductors, and the results will be presented in ISS2020.

 [1] X. Jin, et al., Superconductor Science and Technology 28 (2015) 075010.

Acknowledgements:
This work was supported by MEXT project of Leading Initiative for Excellent Young Researchers (LEADER) Project ID 16810210, and JSPS KAKENHI Grant Number JP18K04719, Japan.

Keywords: REBCO, bulk, superconducting joint, CJMB