The effect of Nd422 content on the trapped field was studied for Nd-Ba-Cu-O superconductors. In this system, there are two dominant pinning centers of Nd422/Nd123 interfaces and chemical fluctuation in the matrix. In the present experiment, the average diameter of Nd422 was larger than 2 μm and thus excess Nd422 deteriorated both Jc-B properties and crystal growth. However, cracking was introduced in large grain samples with small Nd422 content, which could be prevented by increasing Ag2O content from 10 to 20 wt.%. The highest trapped field of 1.4 T was achieved in the sample with a molar ratio of Nd123:Nd422 = 10:1.5 with 20 wt.% Ag2O at 77 K. Furthermore, the secondary peak effect was observed in the field dependence of the trapped field, showing that the field induced pinning is active in large grain samples.
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