title: Coexistence and competition of the short-range incommensurate antiferromagnetic order with the superconducting state of BaFe(2-x)Ni(x)As2.
abstract: 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 BaFe(2-x)T(x)As2 (where T=Co or Ni). Here we use neutron scattering to demonstrate that genuine long-range AF order and superconductivity do not coexist in BaFe(2-x)Ni(x)As2 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.
authors.affiliation: Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Huiqian
authors.initials: H
authors.lastname: Luo
authors.forename: Rui
authors.initials: R
authors.lastname: Zhang
authors.forename: Mark
authors.initials: M
authors.lastname: Laver
authors.forename: Zahra
authors.initials: Z
authors.lastname: Yamani
authors.forename: Meng
authors.initials: M
authors.lastname: Wang
authors.forename: Xingye
authors.initials: X
authors.lastname: Lu
authors.forename: Miaoyin
authors.initials: M
authors.lastname: Wang
authors.forename: Yanchao
authors.initials: Y
authors.lastname: Chen
authors.forename: Shiliang
authors.initials: S
authors.lastname: Li
authors.forename: Sung
authors.initials: S
authors.lastname: Chang
authors.forename: Jeffrey W
authors.initials: JW
authors.lastname: Lynn
authors.forename: Pengcheng
authors.initials: P
authors.lastname: Dai