Structural and magnetic phase diagram of CeFeAsO<SUB>1‑ x</SUB>F<SUB>x</SUB> and its relation to high-temperature superconductivity

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• Huang, Q.
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• de la Cruz, Clarina
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• Li, Shiliang
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• Lynn, J. W.
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• Chen, Y.
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• Green, M. A.
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• Chen, G. F.
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• Li, G.
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• Li, Z.
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• Luo, J. L.
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• Wang, N. L.
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• Dai, Pengcheng

Abstract

Recently, high-transition-temperature (high-T_c) superconductivity was discovered in the iron pnictide RFeAsO_1‑xF_x (R, rare-earth metal) family of materials. We use neutron scattering to study the structural and magnetic phase transitions in CeFeAsO_1‑xF_x as the system is tuned from a semimetal to a high-T_c superconductor through fluorine (F) doping, x. In the undoped state, CeFeAsO develops a structural lattice distortion followed by a collinear antiferromagnetic order with decreasing temperature. With increasing fluorine doping, the structural phase transition decreases gradually and vanishes within the superconductivity dome near x=0.10, whereas the antiferromagnetic order is suppressed before the appearance of superconductivity for x>0.06, resulting in an electronic phase diagram remarkably similar to that of the high-T_c copper oxides. Comparison of the structural evolution of CeFeAsO_1‑xF_x with other Fe-based superconductors suggests that the structural perfection of the Fe–As tetrahedron is important for the high-T_c superconductivity in these Fe pnictides.