Electromagnetic, atomic-structure and chemistry changes induced by Ca-doping of low-angle $YBa_2Cu_3O_{7-δ}$ grain boundaries

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dc.creatorSong, Xueyan
dc.creatorDaniels, George
dc.creatorFeldmann, D. Matt
dc.creatorGurevich, Alex
dc.creatorLarbalestier, David
dc.date2005-05-23
dc.date.accessioned2026-07-07T03:05:18Z
dc.date.available2026-07-07T03:05:18Z
dc.descriptionPractical high temperature superconductors must be textured to minimize the reduction of the critical current density $J_{gb}$ at misoriented grain boundaries. Partial substitution of Ca for Y in $YBa_2Cu_3O_{7-δ}$ has shown significant improvement in $J_{gb}$ but the mechanisms are still not well understood. Here we report atomic-scale, structural and analytical electron microscopy combined with transport measurements on $7^{\circ}$ $[001]$-tilt $Y_{0.7}Ca_{0.3}Ba_2Cu_3O_{7-δ}$ and $YBa_2Cu_3O_{7-δ}$ grain boundaries, where the dislocation cores are well separated. We show that the enhanced carrier density, higher $J_{gb}$ and weaker superconductivity depression at the Ca-doped boundary result from a strong, non-monotonic Ca segregation and structural rearrangements on a scale of ~1 nm near the dislocation cores. We propose a model of the formation of $Ca^{2+}$ solute atmospheres in the strain and electric fields of the grain boundary and show that Ca doping expands the dislocation cores yet enhances $J_{gb}$ by improving the screening and local hole concentration.
dc.description19 pages, 6 Figures
dc.identifierhttps://arxiv.org/abs/cond-mat/0505568
dc.identifierhttp://arxiv.org/abs/cond-mat/0505568
dc.identifierNature Materials, Published online: 22 May 2005; doi:10.1038/nmat1394
dc.identifierdoi:10.1038/nmat1394
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/26401
dc.subjectMaterials Science
dc.titleElectromagnetic, atomic-structure and chemistry changes induced by Ca-doping of low-angle $YBa_2Cu_3O_{7-δ}$ grain boundaries
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