On the crystal structure and magnetic properties of MnNiGe

MnNiGe has been studied by X-ray and neutron diffraction to elucidate its structural and magnetic properties. The structure at room temperature is of the orthorhombic TiNiSi type, but transforms on heating above 528 K to the hexagonal ordered Ni₂In type. Below 356 K a spiral magnetic structure with propagation vector τ = 0.228 × 2πa^* is found. At 260 K an abrupt change in the intensity of the satellite reflections with no change in the propagation vector is attributed to the formation of a double spiral structure. Discrepancies between these findings and the results of previous measurements are attributed to differences in sample preparation.