Doping evolution of antiferromagnetism and transport properties in nonsuperconducting BaFe_(2-2x)Ni_xCr_xAs_2

摘要

We report elastic neutron scattering and transport measurements on the Ni and Cr equivalently doped iron pnictide BaFe_(2-2x)Ni_xCr_xAs_2. Compared with the electron-doped BaFe_(2-x)Ni_xAs_2, the long-range antiferromagnetic (AF) order in BaFe_(2-2x):Ni_xCr_x As_2 is gradually suppressed with vanishing ordered moment and Neel temperature near × = 0.20 without the appearance of superconductivity. A detailed analysis on the transport properties of BaFe_(2-x)Ni_xAs and BaFe_(2-2x)Ni_xCr_xAs_2 suggests that the non-Fermi-liquid behavior associated with the linear resistivity as a function of temperature may not correspond to the disappearance of the static AF order. From the temperature dependence of the resistivity in overdoped compounds without static AF order, we find that the transport properties are actually affected by Cr impurity scattering, which may induce a metal-to-insulator crossover in highly doped BaFe_(1.7-y)Ni_(0.3)Cr_yAs_2.