|Title||Competing Magnetic Fluctuations in Iron Pnictide Superconductors: Role of Ferromagnetic Spin Correlations Revealed by NMR|
|Publication Type||Journal Article|
|Year of Publication||2015|
|Authors||Wiecki, P, Roy, B, Johnston, DC, Bud'ko, SL, Canfield, PC, Furukawa, Y|
|Journal||Physical Review Letters|
|Type of Article||Article|
In the iron pnictide superconductors, theoretical calculations have consistently shown enhancements of the static magnetic susceptibility at both the stripe-type antiferromagnetic and in-plane ferromagnetic (FM) wave vectors. However, the possible existence of FM fluctuations has not yet been examined from a microscopic point of view. Here, using As-75 NMR data, we provide clear evidence for the existence of FM spin correlations in both the hole-and electron-doped BaFe2As2 families of iron-pnictide superconductors. These FM fluctuations appear to compete with superconductivity and are thus a crucial ingredient to understanding the variability of T-c and the shape of the superconducting dome in these and other iron-pnictide families.
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