Magnonic Band Structure Established by Chiral Spin-Density Waves in Thin Film Ferromagnets
arXiv:1812.10571 · doi:10.1109/LMAG.2019.2896540
Abstract
Recent theoretical studies have demonstrated the possibility to excite and sustain noncollinear magnetization states in ferromagnetic nanowires. The resulting state is referred to as a spin-density wave (SDW). SDWs can be interpreted as hydrodynamic states with a constant fluid density and fluid velocity in systems with easy-plane anisotropy. Here, we consider the effect of the nonlocal dipole field arising from the finite thickness of magnetic thin films on the spatial profile of the SDW and on the associated magnon dispersion. Utilizing a hydrodynamic formulation of the Larmor torque equation, it is found that the nonlocal dipole field modulates the fluid velocity. Such a modulation induces a magnonic band structure unlike the typical dispersion relation for magnons on uniform magnetization. The analytical results are validated by micromagnetic simulations. Band gaps on the order of GHz are numerically observed to depend on the SDW fluid velocity and film thickness for realistic material parameters. The presented results suggest that SDWs can find applications as reconfigurable magnonic crystals.
arXiv comment5 pages, 5 figures
References in corpus (19)
- The design and verification of Mumax3
- Collective spin excitations of helices and magnetic skyrmions: review and perspectives of magnonics in non-centrosymmetric magnets
- Spin currents and spin superfluidity
- Superfluid Spin Transport through Easy-Plane Ferromagnetic Insulators
- Experimental Signatures of Spin Superfluid Ground State in Canted Antiferromagnet Cr2O3 via Nonlocal Spin Transport
- Magnetic domain-wall motion by propagating spin waves
- Dissipationless Spin Transport in Thin Film Ferromagnets
- Dynamic response of an artificial square spin ice
- Long-Distance Spin Transport Through a Graphene Quantum Hall Antiferromagnet
- Reconfigurable spin wave band structure of artificial square spin ice
- Voltage-Controlled Nano-Scale Reconfigurable Magnonic Crystal
- Oscillatory Energy Exchange Between Waves Coupled by a Dynamic Artificial Crystal
- Reprogrammable magnonic band structure of layered Permalloy/Cu/Permalloy nanowires
- Breaking of Galilean invariance in the hydrodynamic formulation of ferromagnetic thin films
- Topologically non-trivial magnon bands in artificial square spin ices subject to Dzyaloshinskii-Moriya interaction
- Symmetry-broken dissipative exchange flows in thin-film ferromagnets with in-plane anisotropy
- Analytical theory of modulated magnetic solitons
- Easy-Plane Magnetic Strip as a Long Josephson Junction
- Vortex-antivortex proliferation from an obstacle in thin film ferromagnets