Effect of Nadopant on the Levitation Force of Single Domain.pdf

J Supercond Nov Magn (2011) 24:2211–2214 DOI 10.1007/s10948-011-1183-8 O R I G I NA L PA P E R Effect of Na-dopant on the Levitation Force of Single Domain YBCO Bulk Superconductors Fabricated by TSMTG Process W.M. Yang · Y.L. Tang · G.Z. Li · X.X. Chao · J. Ma Received: 11 February 2011 / Accepted: 3 May 2011 / Published online: 24 May 2011 © Springer Science+Business Media, LLC 2011 Abstract Na-doped single domain YBa Na Cu O Element doping is one of the most important ways 2−x x 3 7−δ (YBCO, x = 0.05, 0.1, 0.15, 0.2, 0.25, 0.3) bulk supercon- to modify the physical properties of YBCO supercon- ductors were prepared by a modified melt textured process ductors, Chen and Kumar [11] have studied the struc- and the effect of Na substitution on the levitation force of tural and thermal properties of (YBa Cu ) Na O 2 3 1−x x 7−δ YBCO bulks have been investigated. The maximum levi- materials, and revealed that the sodium could stabilize tation forces (MLF) are much different for samples with a its orthorhombic structure and selectively replaces yttrium different Na element content. It is found that the optimum in the (YBa Cu ) Na O crystal lattice. Siddiqi’s 2 3 1−x x 7−δ Na element content in YBCO for the strong MLF is around [12] results indicated that the sodium substitution in the x = 0.2. It is also found that the addition of Na could reduce Y0.3Ba0.7−x Nax CuO3−y system reduced the T c valu