Formation of a spiral structure in chiral magnets with impurities

Abstract

We investigate a role of impurity doping on the formation of a spiral structure in a chiral magnet. Our calculations are based on classical Monte Carlo technique and incorporate exchange and Dzyaloshinskii–Moriya interaction in terms of effective localized spins. As an application of our model we consider Co doping in a compound Fe1−xCoxSi. We reveal that adding impurity changes chiral fluctuations, leads to a decrease of the spiral wave vector which completely vanishes at a critical impurity concentrations. We analyze the behavior of the Bragg intensity profile as a function of doping. At an intermediate impurity concentrations we observe a disordered structure characterized by a Bragg spot around q=0 in the q-space.