Mn-induced spin glass behavior in metallic Ir3Sn7-xMnx.

Transition metal stannides are usually semiconductors with a narrow band gap. We report experimental investigation on metallic Ir3Sn7-xMnx(x= 0 and 0.56). Single crystal x-ray diffraction refinement indicates that Ir3Sn7-xMnxcrystals form a cubic structure (space groupIm-3m) with the lattice parametera= 9.362(4) Å forx= 0 and 9.328(6) Å forx= 0.56. The electrical resistivity shows metallic behavior between 2 K and 300 K withT2dependence atT< 30 K forx= 0, reflecting the Fermi-liquid ground state. While Ir3Sn7exhibits weak diamagnetism, partial substitution of Sn by Mn results in spin glass behavior in Ir3Sn7-xMnxwithTg~ 13 K forx= 0.56. Remarkably, an upturn in the resistivity is observed inx= 0.56 below ~2Tg, suggesting strong spin fluctuations. This fluctuation is suppressed by the application of magnetic field, which is reflected in the observation of negative magnetoresistance. The unusual properties that emerge due to Mn doping are discussed further below.