Gd substitution induced incommensurate antiferromagnetism in B20 noncentrosymmetric CoSi.

Rare-earth element Gd doped CoSi, Co1-xGd x Si ( x = 0.01), is investigated using x-ray diffraction and magnetization. It crystallizes in B20 cubic structure with lattice parameter of a = 4.4429 Å. The alloy exhibits two antiferromagnetic transitions AFM-I at 38.44 K and AFM-II at 21.87 K followed by an upturn of magnetization belowTut= 9.79 K as illustrated through the temperature-magnetic field T-H phase diagram. AFM-I state is incommensurate. AFM-II state is weakly correlated as inferred from field-induced transition to AFM-I state. Further, AFM-I state is reported to transform to ferromagnetic state in high magnetic fields. The present study stimulates an approach to derive novel and exotic magnetic materials by substituting rare-earth in transition metal monosilicides.