Theory of magnetic skyrmion glass

Abstract

Skyrmions and skyrmion crystal (SkX) discovered in chiral magnets show unique physical properties due to their nontrivial topology such as the stability against the annihilation and the motion driven by the ultralow current density, which can be advantageous for the device applications such as magnetic memories. Especially, the chiral dynamics, i.e., the velocity perpendicular to the force acting on a skyrmion, is a key to avoid the impurity potential and enhances its mobility. However, the collective pinning of SkX occurs by the disorder, which is crucial for its low energy properties. Here, we study theoretically the low energy dynamics of SkX in the presence of disorder effects in terms of replica field theory, and reveal nonreciprocal collective modes and their electromagnetic responses along the direction of external magnetic field. The physical quantities such as the relaxation rate of $\mu$SR/NMR and the pinning frequency show a dramatic change associated with the topological phase transition from the helical state to SkX. These results provide a firm basis to explore the glassy state of SkX.

14 pages, 4 figures (Accepted for publication in Phys. Rev. B)

References in corpus (11)

• Spontaneous Skyrmion Ground States in Magnetic Metals
• Microscopic approach to current-driven domain wall dynamics
• Magnetoelectric Resonances and Predicted Microwave Diode Effect of Skyrmion Crystal in Multiferroic Chiral-Lattice Magnet
• A mechanism to pin skyrmions in chiral magnets
• Establishing the fundamental magnetic interactions in the chiral skyrmionic Mott insulator Cu2OSeO3 by terahertz electron spin resonance
• Two-loop Functional Renormalization Group of the Random Field and Random Anisotropy O(N) Models
• Electric transport in three-dimensional Skyrmion/monopole crystal
• Experimental evidence for a Bragg glass density wave phase in a transition-metal dichalcogenide
• Phasons and excitations in skyrmion lattice
• Current-driven skyrmion motion along disordered magnetic tracks
• Effect of dilute, strongly pinning impurities on charge density waves

Cited by in corpus (18)

• Statics and Dynamics of Skyrmions Interacting with Pinning: A Review
• Helicity locking of square skyrmion crystal in a centrosymmetric lattice system without vertical mirror symmetry
• First-principles Dzyaloshinskii-Moriya interaction in a non-collinear framework
• Multifarious skyrmion phases on a trilayer triangular lattice
• Skyrmion relaxation dynamics in the presence of quenched disorder
• Nonreciprocal Transport in Noncoplanar Magnetic Systems without Spin-Orbit Coupling, Net Scalar Chirality, or Magnetization
• Transformations from stripy states to skyrmion crystals
• Particle-continuum-medium duality of skyrmions
• Skyrmion crystal under $D_{3h}$ point group: Role of out-of-plane Dzyaloshinskii-Moriya interaction
• Late stages in the ordering of magnetic skyrmion lattices
• Robustness of topological magnons in disordered arrays of skyrmions
• Phase shifts, band geometry and responses in triple-Q charge and spin density waves
• Peak Effect, Melting, and Transport in Skyrmion Crystals
• Sliding Dynamics of Current-Driven Skyrmion Crystal and Helix in Chiral Magnets
• Searching for activated transitions in complex magnetic systems
• Topological Textures in Zr-Substituted Barium Titanate
• Probing Random-Bond Disorder Effects on Ferromagnetic Skyrmion Arrays
• Stacking-dependent nonreciprocal transport in magnetic skyrmions