title: Chiral properties of structure and magnetism in Mn(1-x)Fe(x)Ge compounds: when the left and the right are fighting, who wins?
abstract: 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<x(c). We used x-ray diffraction and polarized neutron scattering to evaluate the crystallographic chirality Γ(c) and the magnetic chirality γ(m) of the FeGe single crystals. Similar to previous observations for FeSi-based compounds, FeGe demonstrates left- (right-)handed crystalline chirality acompained by right (left) handedness of the magnetic helix (Γ(c) γ(m) = -1). At variance, MnSi related compounds show the opposite behavior (Γ(c)γ(m) = 1). Since the magnetic chirality γ(m) relates to the sign of the Dzyaloshinskii-Moriya interaction (DMI), for the same geometrical arrangement (Γ(c)) the sign of DMI can be set by the proper choice of the transition metal.
authors.affiliation: Petersburg Nuclear Physics Institute, 188300 Gatchina, Saint-Petersburg, Russia and Saint-Petersburg State University, Ulyanovskaya 1, 198504 Saint-Petersburg, Russia.
authors.forename: S V
authors.initials: SV
authors.lastname: Grigoriev
authors.affiliation: Petersburg Nuclear Physics Institute, 188300 Gatchina, Saint-Petersburg, Russia.
authors.forename: N M
authors.initials: NM
authors.lastname: Potapova
authors.affiliation: Helmholtz Zentrum Geesthacht, Geesthacht 21502, Germany.
authors.forename: S-A
authors.initials: SA
authors.lastname: Siegfried
authors.affiliation: Petersburg Nuclear Physics Institute, 188300 Gatchina, Saint-Petersburg, Russia and Swiss-Norwegian Beamlines at the European Synchrotron Radiation Facility, 38000 Grenoble, France.
authors.forename: V A
authors.initials: VA
authors.lastname: Dyadkin
authors.affiliation: Petersburg Nuclear Physics Institute, 188300 Gatchina, Saint-Petersburg, Russia and Saint-Petersburg State University, Ulyanovskaya 1, 198504 Saint-Petersburg, Russia.
authors.forename: E V
authors.initials: EV
authors.lastname: Moskvin
authors.affiliation: Swiss-Norwegian Beamlines at the European Synchrotron Radiation Facility, 38000 Grenoble, France.
authors.forename: V
authors.initials: V
authors.lastname: Dmitriev
authors.affiliation: Institut für Physik der Kondensierten Materie, TU Braunschweig, Braunschweig 38106, Germany.
authors.forename: D
authors.initials: D
authors.lastname: Menzel
authors.affiliation: Institute Laue-Langevin, 38042 Grenoble Cedex 9, France.
authors.forename: C D
authors.initials: CD
authors.lastname: Dewhurst
authors.affiliation: Swiss-Norwegian Beamlines at the European Synchrotron Radiation Facility, 38000 Grenoble, France.
authors.forename: D
authors.initials: D
authors.lastname: Chernyshov
authors.affiliation: Institute for High Pressure Physics, Russian Academy of Sciences, 142190 Troitsk, Moscow, Russia and Institute for Nuclear Research, Russian Academy of Sciences, 117312 Moscow, Russia.
authors.forename: R A
authors.initials: RA
authors.lastname: Sadykov
authors.affiliation: Institute for High Pressure Physics, Russian Academy of Sciences, 142190 Troitsk, Moscow, Russia.
authors.forename: L N
authors.initials: LN
authors.lastname: Fomicheva
authors.affiliation: Institute for High Pressure Physics, Russian Academy of Sciences, 142190 Troitsk, Moscow, Russia.
authors.forename: A V
authors.initials: AV
authors.lastname: Tsvyashchenko