The U/n process has been used to introduce quasi-columnar pinning centers into Nd123, textured in 1% O2, 99% Ar. The process involves adding 235U to precursor powders of the superconductor, texturing, and irradiating with thermal neutrons. The two resulting ions, from each nuclear fission, cause aligned discontinuous electronic damage of length ∼5.4 μm, which acts as a pinning center. Best results for Jc require U deposits spaced by s ≤ 5.4 μm. This has been achieved by deposits containing two foreign elements, U and Zr, and three native elements. The deposits of UZrNdBaO and Nd422 refined by the Zr, act as additional non-aligned pinning centers. The U/n process increases Jc by a factor RJ ≥ 10, to values of Jc ∼ 274 kA/cm2 at T = 77 K, B = 666 G.
ASJC Scopus subject areas