Magnetic Properties and Carrier Transport of Ir_0.9Mn_1-xSn_1.1+x

The nonstoichiometric Ir_0.9Mn_1-xSn_1.1+x (x = 0.1, 0.05, and -0.05) are crystallized in half-Heusler alloys. The magnetic transition is observed at 77 K for x = 1.05, and it decreases with the decreasing Mn content. It is proven to be a ferromagnetic transition with a nonlinear magnetic moment alignment, as the magnetization is not saturated at 70 kOe. The different magnetic behavior than a typical ferromagnet (FM is due to the Ir ions with strong spin orbital coupling (SOC). The different hysteresis loops reflect that the ionic distribution is not completely homogeneous. The high coercivity observed in the cubic compound is due to the strong single-ion anisotropy of the Ir ions. A metallic-semiconducting transition at 130 K is observed in Ir_0.9Mn_1.05Sn_1.05. A negative magnetoresistance is observed at 2 K and 14 T with the value as -2.6%.