Abstract
The effect of Nd2O3, BaCO3, Nd(422), Y1/Nd1(211) and PtO2 dopants on the microstructure and superconducting properties of melt-processed Y0.5/Nd0.5(123) has been studied. Within measurement error, each sample showed no evidence for Nd3+ substituting on Ba2+ sites. Microstructural analysis indicated that enriching the starting composition, Y0.5/Nd0.5(123) with Nd resulted in a significant preference for Nd to dominate the rare-earth (Re) site in the (123) melt-textured phase. The formation of the non-superconducting Y/Nd(211) phase was found to be inhomogeneous, non-uniform and normally dominated by Y. All samples exhibited Tc values exceeding 91 K with sharp transitions, except for those doped with the 211 phase. Magnetization measurements for all samples over the magnetic field range 0 to 1 T showed no indication for the formation of a second peak effect in the M–H loops, while the addition of Nd-rich phases improved Jc at high fields. Refinement of the Y/Nd(211) inclusions does not apparently improve Jc. The highest Jc measured was ∼11 200 A/cm2 at 77 K and 0 T, for a sample with excess Nd(422) and PtO2.