Spin current generation driven by skyrmion dynamics under magnetic anisotropy and polarized microwaves

Abstract

We have investigated the spin-current pumped by the skyrmion-host material with the lack of inversion symmetry through the microwave resonance process. The effects of magnetic anisotropy and polarized microwaves are examined by micromagnetic simulations. Our results reveal two distinct skyrmion phases, designated as SkX type-I and II, which emerge at low ($K_z<0.1$ meV) and high ($K_z>0.1$ meV) magnetic anisotropy constants, respectively, having different characteristics of spin excitations. The SkX type-I exhibits spin dynamics where the resonant frequency of the breathing mode is lying in between the clockwise and counterclockwise gyration modes of Bloch-type skyrmion at a very low anisotropy, and is crossing over the counterclockwise mode at $K_z\sim 0.04$ meV. Meanwhile, the SkX type-II exhibits distinct spin excitations in which the clockwise mode is notably absent, while the counterclockwise modes exist at both low and high resonant frequencies. This suggests that the magnetic anisotropy plays an essential role in the spin dynamics. Furthermore, the resulting spin excitations induce spin currents with exotic features under the polarized microwaves. The spin currents induced, for instance, by low-lying in-plane excitations are strongly enhanced under the left-handed circularly polarized microwaves, but quenched by the right-handed circularly polarized microwaves regardless of the sign of the Dzyaloshinskii-Moriya interaction. These results may pave the way for understanding the non-trivial interplay between magnetic anisotropy and polarized microwaves in the generation of spin currents by a resonant process.

8 pages, 8 figures

References in corpus (24)

• Skyrmion Lattice in a Chiral Magnet
• Enhanced Gilbert Damping in Thin Ferromagnetic Films
• Topological Hall effect in the A-phase of MnSi
• Direct Observation of the Skyrmion Hall Effect
• Emergent electrodynamics of skyrmions in a chiral magnet
• Spin pumping and magnetization dynamics in metallic multilayers
• Atomistic spin model simulations of magnetic nanomaterials
• Skyrmion lattice with a giant topological Hall effect in a frustrated triangular-lattice magnet
• Spin-Wave Modes and Their Intense Excitation Effects in Skyrmion Crystals
• Skyrmion phase and competing magnetic orders on a breathing kagome lattice
• Skyrmions and Anomalous Hall Effect in a Dzyloshinskii-Moriya Spiral Magnet
• Observation of magnetic excitations of skyrmion crystal in a helimagnetic insulator
• Depinning and nonequilibrium dynamic phases of particle assemblies driven over random and ordered substrates: a review
• Spin Torques in Ferromagnetic/Normal Metal Structures
• First-principles study of magnetization relaxation enhancement and spin-transfer in thin magnetic films
• Statics and Dynamics of Skyrmions Interacting with Pinning: A Review
• Topological spin waves in the atomic-scale magnetic skyrmion crystal
• Formation of a topological non-Fermi liquid in MnSi
• Magnetic Excitations in the Multiferroic Néel-type Skyrmion Host GaV${}_4$S${}_8$
• Microwave resonances of magnetic skyrmions in thin film multilayers
• Effective damping enhancement in noncollinear spin structures
• Ferromagnetic resonance in systems with competing uniaxial and cubic anisotropies
• Generation of Spin Currents in the Skyrmion Phase of a Helimagnetic Insulator $\mathrm{C}{\mathrm{u}}_2\mathrm{OSe}{\mathrm{O}}_3$
• Spin current pumped by resonant skyrmion