Nanoscale strain-induced pair suppression as a vortex-pinning mechanism in high-temperature superconductors.

Abstract

Boosting large-scale superconductor applications require nanostructured conductors with artificial pinning centres immobilizing quantized vortices at high temperature and magnetic fields. Here we demonstrate a highly effective mechanism of artificial pinning centres in solution-derived high-temperature superconductor nanocomposites through generation of nanostrained regions where Cooper pair formation is suppressed. The nanostrained regions identified from transmission electron microscopy devise a very high concentration of partial dislocations associated with intergrowths generated between the randomly oriented nanodots and the epitaxial YBa(2)Cu(3)O(7) matrix. Consequently, an outstanding vortex-pinning enhancement correlated to the nanostrain is demonstrated for four types of randomly oriented nanodot, and a unique evolution towards an isotropic vortex-pinning behaviour, even in the effective anisotropy, is achieved as the nanostrain turns isotropic. We suggest a new vortex-pinning mechanism based on the bond-contraction pairing model, where pair formation is quenched under tensile strain, forming new and effective core-pinning regions.

• Authors: A Llordés, A Palau, J Gázquez, M Coll, R Vlad, A Pomar, J Arbiol, R Guzmán, S Ye, V Rouco, F Sandiumenge, S Ricart, T Puig, M Varela, D Chateigner, J Vanacken, J Gutiérrez, V Moshchalkov, G Deutscher, C Magen, X Obradors
• Journal: Nature materials (Nat Mater) Vol. 11 Issue 4 Pg. 329-36 (Feb 12 2012) ISSN: 1476-4660 [Electronic] England
• PMID: 22327747 (Publication Type: Journal Article)