Localization induced by pressure in pyrochlore Bi2Ir2O7

In this work, the resistivity and magnetization of Bi2Ir2O7 are investigated under hydrostaticpressure. At ambient pressure, the resistivity of Bi2Ir2O7 exhibits a metallic behavior with thedecrease of temperature. When the pressure is applied, a metal-insulator phase transition at lowtemperature is induced under a pressure of 0.48 GPa. The metal-insulator phase transition temperature(TMI ) increases linearly with pressure as dTMI/dP = 3.4 0.3 K/GPa. The temperaturedependence of resistivity [(T)] in the pressure-induced insulating phase exhibits a thermal activationbehavior ( = 0eΔE=kBT ), where the thermal activation energy (ΔE) increases monotonouslywith the pressure. Meanwhile, the magnetization is enhanced by the pressure, which indicates anenhancement of magnetic ordering. The results suggest that localization occurs due to the magneticordering induced by the pressure, which confirms the magneto-electronic coupling in Bi2Ir2O7