Influence of Fe buffer thickness on the crystalline quality and the transport properties of Fe/Ba(Fe1-xCox)2As2 bilayers

The implementation of an Fe buffer layer is a promising way to obtain epitaxial growth of Co-doped BaFe2As2 (Ba-122). However, the crystalline quality and the superconducting properties of Co-doped Ba-122 are influenced by the Fe buffer layer thickness, d(Fe). The well-textured growth of the Fe/Ba-122 bilayer with d(Fe) = 15 nm results in a high J(c) of 0.45 MA cm(-2) at 12 K in self-field, whereas a low J(c) value of 61 000 A cm(-2) is recorded for the bilayer with d(Fe) = 4 nm at the corresponding reduced temperature due to the presence of grain boundaries. (C) 2010 American Institute of Physics. [doi:10.1063/1.3509418]