American Physical Society, Physical review B, 21(86)
DOI: 10.1103/physrevb.86.214504
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We report on the superior vortex pinning of single- and multilayer Ba(Fe1−xCox)2As2 thin films with self-assembled c-axis and artificially introduced ab-plane pins. Ba(Fe1−xCox)2As2 can accept a very high density of pins (15–20 vol %) without Tc suppression. The matching field is greater than 12 T, producing a significant enhancement of the critical current density Jc, an almost isotropic Jc(θ, 20 T) > 105 A/cm2, and global pinning force density Fp of ∼50 GN/m3. This scenario strongly differs from the high-temperature superconducting cuprates where the addition of pins without Tc suppression is limited to 2–4 vol %, leading to small HIrr enhancements and improved Jc only below 3–5 T.