Doping evolution of antiferromagnetism and transport properties in the non-superconducting BaFe_2-2xNi_xCr_xAs₂

We report elastic neutron scattering and transport measurements on the Ni and Cr equivalently doped iron pnictide BaFe_2-2xNi_xCr_xAs₂. Compared with the electron-doped BaFe_2-2xNi_xCr_xAs₂, the long-range antiferromagnetic (AF) order in BaFe_2-2xNi_xCr_xAs₂ is gradually suppressed with vanishing ordered moment and Neel temperature near x= 0.20 without the appearance of superconductivity. A detailed analysis on the transport properties of BaFe_2-xNi_xAs and BaFe_2-xNi_xAs and BaFe_2-2xNi_xCr_xAs₂ 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-yNi_0.3Cr_yAs₂.