Unpinning the skyrmion lattice in MnSi:Effect of substitutional disorder

Abstract

By employing magnetization and small angle neutron scattering (SANS) measurements, we have investigated the behavior of the skyrmion lattice (SKL) and the helical order in MnSi0.992Ga0.008. Our results indicate that the order of the SKL is sensitive to the orientation of an applied magnetic field with respect to the crystal lattice and small variations in the sequence of temperature and applied magnetic field changes. The disorder caused by the substitution of the heavier element Ga for Si is sufficient to reduce the pinning of the SKL to the underlying crystalline lattice. This reduces the propensity for the SKL to be aligned with the crystal lattice. This tendency is most evident when the applied field is not well oriented with respect to the high symmetry axes of the crystal resulting in disorder in the long range SKL while maintaining sharp radial order. We have also investigated the effect of substituting heavier elements into MnSi on the reorientation process of the helical domains with field cycling in MnSi0.992Ga0.008 and Mn0.985Ir0.015Si. A comparison of the reorientation process in these materials with field reduction indicates that the substitution of heavier elements on either Mn or Si sites creates a higher energy barrier for the reorientation of the helical order and for the formation of domains.

7 Figures,21 pages

References in corpus (21)

• A new class of chiral materials hosting magnetic skyrmions beyond room temperature
• Long wavelength helimagnetic order and skyrmion lattice phase in Cu2OSeO3
• Magnetic phase diagram of MnSi inferred from magnetization and ac susceptibility
• Magnetic Skyrmions on a Two-Lane Racetrack
• Multidomain Skyrmion Lattice State in Cu${}_2$OSeO${}_3$
• A mechanism to pin skyrmions in chiral magnets
• Topological domain walls in helimagnets
• Symmetry breaking, slow relaxation dynamics, and topological defects at the field-induced helix reorientation in MnSi
• History dependence of the magnetic properties of single-crystal Fe${}_{1-x}$Co${}_x$Si
• Dynamical defects in rotating magnetic skyrmion lattices
• Theory of magnetic skyrmion glass
• Reorientations, relaxations, metastabilities and multidomains of skyrmion lattices
• Extended skyrmion lattice scattering and long-time memory in the chiral magnet Fe${}_{1-x}$Co${}_x$Si
• Effect of Negative Pressure on the Prototypical Itinerant Magnet MnSi
• Response of the skyrmion lattice in MnSi to cubic magnetocrystalline anisotropies
• Evolution of magneto-crystalline anisotropies in Mn${}_{1-x}$Fe${}_x$Si and Mn${}_{1-x}$Co${}_x$Si as inferred from small-angle neutron scattering and bulk properties
• Exploring the origins of the Dzyalloshinski-Moria interaction in MnSi
• Formation process of skyrmion lattice domain boundaries: The role of grain boundaries
• Evolution of helimagnetic correlations in Mn${}_{1-x}$Fe${}_x$Si with doping: a small-angle neutron scattering study
• Anisotropic magneto-crystalline coupling of the skyrmion lattice in MnSi
• Helical and skyrmion lattice phases in three-dimensional chiral magnets: Effect of anisotropic interactions

Cited by in corpus (4)

• Increased lifetime of metastable skyrmions by doping
• Measuring the Formation Energy Barrier of Skyrmions in Zinc Substituted Cu${}_2$OSeO${}_3$
• Entropic signatures of the skyrmion lattice phase in MnSi1-xAlx and Fe1-yCoySi
• Comparison of skyrmion phases between poly and single-crystal MnSi by composite magnetoelectric method