Superconductivity in the iron pnictides develops near antiferromagnetism, and the antiferromagnetic (AF) phase appears to overlap with the superconducting phase in some materials such as BaFe2-xTxAs2 (where T = Co or Ni). Here we use neutron scattering to demonstrate that genuine long-range AF order and superconductivity do not coexist in BaFe2-xNixAs2 near optimal superconductivity. In addition, we find a first-order-like AF-to-superconductivity phase transition with no evidence for a magnetic quantum critical point. Instead, the data reveal that incommensurate short-range AF order coexists and competes with superconductivity, where the AF spin correlation length is comparable to the superconducting coherence length.
Bibliographical note© 2012 American Physical Society
Luo, H., Zhang, R., Laver, M., Yamani, Z., Wang, M., Lu, X., Wang, M., Chen, Y., Li, S., Chang, S., Lynn, J. W., & Dai, P. (2012). Coexistence and Competition of the Short-Range Incommensurate Antiferromagnetic Order with the Superconducting State of BaFe2-xNixAs2. Physical Review Letters, 108(24), -. https://doi.org/10.1103/PhysRevLett.108.247002