Exploring Magnetic Excitations in Fe-Doped MnNiGe Alloys through Inelastic Neutron Scattering

Depending on the doping site, Fe-doping significantly modifies the modulation of the incommensurate magnetic structure of MnNiGe alloy of the magnetic equiatomic alloy family. The pristine MnNiGe alloy was reported to show a helically modulated antiferromagnetic (AFM) structure. Recent neutron powder diffraction results from our group (data recorded at WISH diffractometer) indicate that helical modulation of the AFM structure remains unperturbed (except the change in propagation vector) when Fe is doped at the non-magnetic Ni-site. However, the modulation becomes cycloidal in the case of Fe-doping at the Mn-site. Such change in AFM modulation may also influence the magnetic excitation behavior (spin wave/spin fluctuation). The present proposal aimed to probe such changes in excitation behavior through inelastic neutron scattering studies at MARI of two Fe-doped alloys on nominal compositions MnNi0.75Fe0.25Ge and Mn0.85Fe0.15NiGe.