Resistivity of Mn_(1-xFe_xSi Single Crystals: Evidence for Quantum Critical Behavior

摘要

Resistivity measurements have been made on Mn_(1-x)Fe_xSi single crystals between 2 and 300 K for x = 0, 0.05, 0.08, 0.12 and 0.15. Fe doping is found to depress the magnetic ordering temperature from 30 K for x = 0 to below 2 K for x = 0.15. Although Fe doping results in a large increase of the low-temperature residual resistivity, the temperature dependence of the resistivity above the magnetic transition remains practically unaffected by increasing Fe content. An analysis of the temperature derivative of the resistivity provides strong evidence for the existence of a non-Fermi-liquid ground state near x = 0.15 and thus for a quantum critical point tuned by Fe content.