Discrete helicoidal states in chiral magnetic thin films

Abstract

Magnetometry and magnetoresistance measurements in MnSi thin films and rigorous analytical solutions of the micromagnetic equations show that the field-induced unwinding of confined helicoids occurs via discrete steps. A comparison between the magnetometry data and theoretical results shows that finite size effects confine the wavelength and lead to a quantization of the number of turns in the helicoid. We demonstrate a prototypical spintronic device where the magnetic field can push or pull individual turns into a magnetic spring that can be read by electrical means

Neutron study of in-plane skyrmions in MnSi thin films

“…For the three remaining field values, the model calculations fit α, R + and R − equally well and therefore only α is shown. Similar to measurements at T = 5 K, 28 we find that the magnetic structure is in a twisted ferromagnetic state in fields above H α2 . By using the experimentally determined values L D and M s as input parameters, we calculated the magnetic structure using the discrete helicoidal model of Ref.…”

“…At T = 5 K, PNR provides proves that the system transitions from a twisted ferromagnetic to a set of discrete helicoidal states as the field is lowered. This is supported by magnetometry, magnetoresistance and theoretical calculations: Analytical solutions to a finite-size 1D Dzyaloshinskii model explain the thickness dependence of the transition fields and variations in the sign of the low-field magnetoresistance 28 . The model shows that for a film thickness d < L D , the system has no peaks in the field dependence of dM/dH, and it transitions continuously from a twisted ferromagnet to a partial helix as the H is lowered.…”

“…The PNR experiments were performed in successively decreasing magnetic fields at the (H, T ) points shown by the yellow stars (this study), and by the yellow triangles (Ref. 28). The cyancolored area taken from Ref.…”

Formation of In-plane Skyrmions in Epitaxial MnSi Thin Films as Revealed by Planar Hall Effect

“…6]. At low temperatures, where we demonstrate the in-plane skyrmion formation, a polarized neutron reflectometry study 27 has proposed a helicoidal state. The helicoidal state proposed in Ref.…”

New Type of Stable Particlelike States in Chiral Magnets

“…For the SkT and ChB this angle ϕ 0 15 • (see Fig.2). Recently the effect of the chiral surface twist has been proven experimentally [25,26]. Everywhere within the conical phase the lowest energy metastable state corresponds to the that shown in Fig.…”