title: Effects of transition metal substitutions on the incommensurability and spin fluctuations in BaFe2As2 by elastic and inelastic neutron scattering.
abstract: The spin fluctuation spectra from nonsuperconducting Cu-substituted, and superconducting Co-substituted, BaFe(2)As(2) are compared quantitatively by inelastic neutron scattering measurements and are found to be indistinguishable. Whereas diffraction studies show the appearance of incommensurate spin-density wave order in Co and Ni substituted samples, the magnetic phase diagram for Cu substitution does not display incommensurate order, demonstrating that simple electron counting based on rigid-band concepts is invalid. These results, supported by theoretical calculations, suggest that substitutional impurity effects in the Fe plane play a significant role in controlling magnetism and the appearance of superconductivity, with Cu distinguished by enhanced impurity scattering and split-band behavior.
authors.affiliation: Ames Laboratory, U.S. DOE, Ames, Iowa 50011, USA.
authors.forename: M G
authors.initials: MG
authors.lastname: Kim
authors.forename: J
authors.initials: J
authors.lastname: Lamsal
authors.forename: T W
authors.initials: TW
authors.lastname: Heitmann
authors.forename: G S
authors.initials: GS
authors.lastname: Tucker
authors.forename: D K
authors.initials: DK
authors.lastname: Pratt
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authors.initials: SN
authors.lastname: Khan
authors.forename: Y B
authors.initials: YB
authors.lastname: Lee
authors.forename: A
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authors.lastname: Alam
authors.forename: A
authors.initials: A
authors.lastname: Thaler
authors.forename: N
authors.initials: N
authors.lastname: Ni
authors.forename: S
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authors.lastname: Ran
authors.forename: S L
authors.initials: SL
authors.lastname: Bud'ko
authors.forename: K J
authors.initials: KJ
authors.lastname: Marty
authors.forename: M D
authors.initials: MD
authors.lastname: Lumsden
authors.forename: P C
authors.initials: PC
authors.lastname: Canfield
authors.forename: B N
authors.initials: BN
authors.lastname: Harmon
authors.forename: D D
authors.initials: DD
authors.lastname: Johnson
authors.forename: A
authors.initials: A
authors.lastname: Kreyssig
authors.forename: R J
authors.initials: RJ
authors.lastname: McQueeney
authors.forename: A I
authors.initials: AI
authors.lastname: Goldman