Gong, DongliangXie, TaoLu, XingyeRen, CongShan, LeiZhang, RuiDai, PengchengYang, Yi-fengLuo, HuiqianLi, Shiliang2016-06-272016-06-272016Gong, Dongliang, Xie, Tao, Lu, Xingye, et al.. "Electronic specific heat in BaFe2−xNixAs2." <i>Physical Review B,</i> 93, no. 13 (2016) American Physical Society: http://dx.doi.org/10.1103/PhysRevB.93.134520.https://hdl.handle.net/1911/90578We have systematically studied the low-temperature specific heat of the BaFe2−xNixAs2 single crystals covering the whole superconducting dome. Using the nonsuperconducting heavily overdoped x=0.3 sample as a reference for the phonon contribution to the specific heat, we find that the normal-state electronic specific heats in the superconducting samples may have a nonlinear temperature dependence, which challenges previous results in the electron-doped Ba-122 iron-based superconductors. A model based on the presence of ferromagnetic spin fluctuations may explain the data between x=0.1 and x=0.15, suggesting the important role of Fermi-surface topology in understanding the normal-state electronic states.engArticle is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.Journal articlehttp://dx.doi.org/10.1103/PhysRevB.93.134520