Abstract
The appearance of superconductivity in the antiferromagnet of BaFe 2As2 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 TC 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 TC and remains in place below.
Original language | English |
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Article number | 024512 |
Journal | Physical Review B - Condensed Matter and Materials Physics |
Volume | 84 |
Issue number | 2 |
DOIs | |
State | Published - Jul 12 2011 |