Evidence of local disorder in the overdoped regime of Ba(Fe(1-x)Co(x))(2)As(2)
|Title||Evidence of local disorder in the overdoped regime of Ba(Fe(1-x)Co(x))(2)As(2)|
|Publication Type||Journal Article|
|Year of Publication||2011|
|Authors||Park K, Louca D, Llobet A, Yan JQ|
|Journal Title||Physical Review B|
The appearance of superconductivity in the antiferromagnet of BaFe(2)As(2) with Co doping coincides with a phase transition from an orthorhombic to a tetragonal structure where coexistence of the two is observed near the phase boundary. Overdoping brings suppression of T(C) near x = 0.12 that is not accompanied by a transition back to the orthorhombic phase. Using pulsed neutron powder diffraction, the relation of superconductivity to the atomic structure in the overdoped regime has been investigated. The suppression of superconductivity is accompanied by a structural local distortion around Co. The distortion, described as a breathing mode with alternating two or four Fe ions displaced toward Co in the ab plane, sets in above T(C) and remains in place below.