Anisotropy of strong pinning in multi-band superconductors

Abstract

The field-angular dependence and anisotropy of the critical current density in iron-based superconductors is evaluated using a phenomenological approach featuring distinct anisotropy factors for the penetration depth and the coherence length. Both the weak collective pinning limit, and the strong pinning limit relevant for iron-based superconductors at low magnetic fields are considered. It is found that in the more anisotropic materials, such as SmFeAsO and NdFeAsO, the field-angular dependence is completely dominated by the coherence-length (upper-critical field) anisotropy, thereby explaining recent results on the critical current in these materials. In less anisotropic superconductors, strong pinning can lead to an apparent inversion of the anisotropy. Finally, it is shown that, under all circumstances, the ratio of c-axis and ab-plane critical current densities for magnetic field along the ab-plane directly yields the coherence length anisotropy factor εξ.

21 pages, 2012 Special Issue on Iron Based Superconductors in Superconducting Science and Technology (accepted); glitches removed on May 31st, 2012; further typos removed Sept. 15th, 2012

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Cited by in corpus (10)

• Intrinsic pinning and the critical current scaling of clean epitaxial Fe(Se,Te) thin films
• Oxypnictide SmFeAs(O,F) superconductor: a candidate for high-field magnet applications
• High-field transport properties of a P-doped BaFe2As2 film on technical substrate
• Bulk magnetization and strong intrinsic pinning in Ni-doped BaFe2As2 single crystals
• Unusually high critical current of clean P-doped BaFe2As2 single crystalline thin film
• Lessons from Oxypnictide Thin Films
• Experimental observation of an anomalous peak in isofield M(T) curves in BaFe${}_2$(As${}_{1-x}$P${}_x$)${}_2$ resembling the fish-tail in $M$($H$) curves further suggesting a possible phase transition in the irreversible regime
• Scaling laws for the critical current density in anisotropic biaxial superconductors
• Vortex dynamics as a function of field orientation in BaFe1.9Ni0.1As2
• Conventional s-wave superconductivity and hidden peak effect in single crystals of Mo${}_8$Ga${}_{4}1$ superconductor