Chiral Properties of Structure and Magnetism in Mn 1-x Fe x Ge Compounds: When the Left and the Right are Fighting, Who Wins?
Magnetic susceptibility measurements have shown that the compounds Mn 1-x Fe x Ge are magnetically ordered through the whole range of concentrations x=[0.0,1.0] . Small-angle neutron scattering reveals the helical nature of the spin structure with a wave vector, which changes from its maximum (|k|=2.3 nm −1 ) for pure MnGe, through its minimum (|k|→0 ) at x c ≈0.75 , to the value of |k|=0.09 nm −1 for pure FeGe. The macroscopic magnetic measurements confirm the ferromagnetic nature of the compound with x=x c . The observed transformation of the helix structure to the ferromagnet at x=x c is explained by different signs of chirality for the compounds with x>x c and x