Evolution of helimagnetic correlations in Mn1−xFexSi with doping: A small-angle neutron scattering study

Abstract

We present a comprehensive small angle neutron scattering study of the doping dependence of the helimagnetic correlations in Mn1−xFexSi. The long-range helimagnetic order in Mn1−xFexSi is suppressed with increasing Fe content and disappears for x > x * ≈ 0.11, i.e. well before xC ≈ 0.17 where the transition temperature vanishes. For x > x * , only finite isotropic helimagnetic correlations persist which bear similarities with the magnetic correlations found in the precursor phase of MnSi. Magnetic fields gradually suppress and partly align these short-ranged helimagnetic correlations along their direction through a complex magnetization process.

Evolution of magnetocrystalline anisotropies in Mn1−xFexSi and Mn1−xKindervater1, Adams2, Bauer3 et al. 2020Phys. Rev. B214170View full textAdd to dashboardCite

“…4(a1)-4(a3), 4(A1)-4(A3), and 5(a). This observation is in excellent agreement with the literature and confirms the well-established 111 easy axes for the helical modulation direction in MnSi [5,11,22,31,45,92] 111 axes in these scattering planes, as shown in Figs. 4(a1) and 4(a3), respectively.…”

“…In a different set of studies, magnetization, susceptibility and SANS were reported for Mn 1−x Fe x Si up to x = 0.32 [91,92]. The magnetization and susceptibility confirmed earlier work, lacking information on anisotropies.…”

“…The magnetization and susceptibility confirmed earlier work, lacking information on anisotropies. Further, the SANS measurements claim to observe a change of the direction of zero-field-cooled helimagnetic order from 111 to 110 without offering any theoretical explanation whatsoever [92]. Moreover, data reported in this paper was recorded for one crystallographic orientation only without further information on the full three-dimensional intensity distribution.…”

Anisotropy-induced depinning in the Zn-substituted skyrmion host Cu2OSeO3

“…One way to control the relative contribution of these energy terms is by varying the elemental composition of skyrmion-hosting materials via chemical substitution or doping. Compositional effects have been studied in a range of systems, such as Fe 1−x Co x Si [34][35][36], Mn 1−x (Fe/Co) x Si [37][38][39][40], Mn 1−x Fe x Ge [41][42][43][44], MnSi 1−x Ge x [45], Co 10−x Zn 10−y Mn x+y [16,22,23,46], Co 8−x (Fe/Ni/Ru) x Zn 8 Mn 4 [47], GaV 4 (S 8−x Se x ) [48,49], [Cu 1−x (Zn/Ni) x ] 2 OSeO 3 [50][51][52][53][54][55], and Cu 2 OSe 1−x Te x O 3 [56]. The properties altered include variation of T c , indicating a change in the exchange interaction strength; alteration of the magnitude and sign of the DMI, leading to changes in the helical and skyrmion lattice periodicity and chirality; switching of the magnetic easy axes, and therefore the helical ground-state domain orientation, by tuning of the cubic anisotropy constants; and modification of the spin wave propagation.…”

Small Angle Neutron Scattering Study near the Critical Field at Low Temperature in MnSi

“…The SkL phase and the phenomena near T c in MnSi have been investigated in detail, for instance, reorientations, relaxation, metastabilities, and multidomains of SkL [13], and magnetic fluctuations, precursor phenomena, and phase transition under magnetic field [14]. The doping dependence of the helimagnetic correlations in Mn 1-x Fe x Si was studied systematically by means of the magnetic susceptibility, magnetization and SANS [15,16]. These reports focused on the SkL phase appeared in the magnetic field-temperature (B-T) phase diagram just below T c .…”