Self-seeded melt growth of Au-doped Nd-Ba-Cu-O

Nd-Ba-Cu-O (NdBCO) precursor powder composed primarily of NdBa2Cu3O7-δ (Nd-123) and 15 mol% Nd4Ba2Cu2O10 (Nd-422) containing 0.1 wt% Au has been prepared by spray drying and subsequent calcination for the fabrication of bulk melt-processed ceramics. The addition of Au results in the lowering of key process parameters, such as the peritectic melting point and solidification temperatures by up to 30 °C. Additional doping of Au/NdBCO with 5 wt% Ag2O lowers these values further and has enabled the successful nucleation and limited growth of single grains under both air and reduced oxygen atmospheres using undoped NdBCO as a seed. The advantage of this self-seeded melt growth technique is that it avoids the lattice mismatch that results from the conventional use of a MgO seed.