Enhanced superfluid density on twin boundaries in Ba(Fe1-xCox)2As2

Research paper by Beena Kalisky, John R. Kirtley, James G. Analytis, Jiun-Haw Chu, Arturas Vailionis, Ian R. Fisher, Kathryn A. Moler

Indexed on: 11 Aug '09Published on: 11 Aug '09Published in: Physics - Superconductivity


Superconducting quantum interference device (SQUID) microscopy shows stripes of increased diamagnetic susceptibility in underdoped, but not overdoped, single crystals of Ba(Fe1-xCox)2As2. These stripes of increased diamagnetic susceptibility are consistent with enhanced superfluid density on twin boundaries. Individual vortices avoid pinning on or crossing the stripes, and prefer to travel parallel to them. These results indicate a relationship between superfluid density, local strain, and frustrated magnetism, and demonstrate two mechanisms for enhancing critical currents.