Nanoscale strain-induced pair suppression as a vortex-pinning mechanism in high-temperature superconductors.
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.
Institut de Ciència de Materials de Barcelona, ICMAB-CSIC, Campus de la UAB, 08193 Bellaterra, Catalonia, Spain.
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Llordés
A
A
Palau
J
J
Gázquez
M
M
Coll
R
R
Vlad
A
A
Pomar
J
J
Arbiol
R
R
Guzmán
S
S
Ye
V
V
Rouco
F
F
Sandiumenge
S
S
Ricart
T
T
Puig
M
M
Varela
D
D
Chateigner
J
J
Vanacken
J
J
Gutiérrez
V
V
Moshchalkov
G
G
Deutscher
C
C
Magen
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X
Obradors