CC BY 4.0 UnportedIida, KazumasaGrinenko, VadimKurth, FritzIchinose, AtaruTsukada, IchiroAhrens, EikePukenas, AurimasChekhonin, PaulSkrotzki, WernerTeresiak, AngelikaHühne, RubenAswartham, SaicharanWurmehl, SabineErbe, ManuelaHänisch, JensHolzapfel, BernhardDrechsler, Stefan-LudwigEfremov, Dmitri V.2018-07-192019-06-282016https://doi.org/10.34657/4967https://oa.tib.eu/renate/handle/123456789/1476The Hall effect is a powerful tool for investigating carrier type and density. For single-band materials, the Hall coefficient is traditionally expressed simply by , where e is the charge of the carrier, and n is the concentration. However, it is well known that in the critical region near a quantum phase transition, as it was demonstrated for cuprates and heavy fermions, the Hall coefficient exhibits strong temperature and doping dependencies, which can not be described by such a simple expression, and the interpretation of the Hall coefficient for Fe-based superconductors is also problematic. Here, we investigate thin films of Ba(Fe1−xCox)2As2 with compressive and tensile in-plane strain in a wide range of Co doping. Such in-plane strain changes the band structure of the compounds, resulting in various shifts of the whole phase diagram as a function of Co doping. We show that the resultant phase diagrams for different strain states can be mapped onto a single phase diagram with the Hall number. This universal plot is attributed to the critical fluctuations in multiband systems near the antiferromagnetic transition, which may suggest a direct link between magnetic and superconducting properties in the BaFe2As2 system.application/pdfapplication/pdfenghttps://creativecommons.org/licenses/by/4.0/620Superconducting properties and materialsArticle