Memory effects on the current induced propagation of spin textures in NdCo${}_5$/Ni${}_8$Fe${}_2$ bilayers

Abstract

Bilayers of NdCo${}_5$/Ni${}_8$Fe${}_2$ can act as reconfigurable racetracks thanks to the parallel stripe domain configuration present in the hard magnetic material with weak perpendicular anisotropy (NdCo${}_5$), and its imprint on the soft magnetic layer (Ni${}_8$Fe${}_2$). This pattern hosts spin textures with well defined topological charges and establishes paths for their deterministic propagation under the effect of pulsed currents, which has been studied as a function of externally applied fields by using Magnetic Transmission X-ray Microscopy. The experiments show guided vortex/antivortex propagation events within the Ni${}_8$Fe${}_2$ above a threshold current of $3\cdot 10^{11}$ A/m${}^2$. Opposite propagation senses have been observed depending on the topological charge of the spin texture, both in the remnant state and under an applied external field. Micromagnetic simulations of our multilayer reveal that the guiding effect and asymmetric propagation sense are due to the magnetic history of the hard magnetic layer. An exchange-bias-based memory effect acts as a magnetic spring and controls the propagation sense by favoring a specific orientation of the in plane magnetization, leading to a system which behaves as a hard-soft magnetic composite with reconfigurable capabilities for a controlled propagation of magnetic topological textures.

References in corpus (16)

• The design and verification of Mumax3
• Beyond skyrmions: Review and perspectives of alternative magnetic quasiparticles
• Magnetic bimerons as skyrmion analogues in in-plane magnets
• Vortices in thin ferromagnetic films and the skyrmion number
• Joule heating in nanowires
• Thermally stable magnetic skyrmions in multilayer synthetic antiferromagnetic racetracks
• Guiding superconducting vortices by magnetic domain walls
• Domain wall automotion in three-dimensional magnetic helical interconnectors
• Topological defects and misfit strain in magnetic stripe domains of lateral multilayers with perpendicular magnetic anisotropy
• Typical skyrmions versus bimerons: a long-distance competition in ferromagnetic racetracks
• Controlled nucleation of topological defects in the stripe domain patterns of Lateral multilayers with Perpendicular Magnetic Anisotropy: competition between magnetostatic, exchange and misfit interactions
• Quantum computing on magnetic racetracks with flying domain wall qubits
• Tunable stochasticity in an artificial spin network
• Current-induced H-shaped-skyrmion creation and their dynamics in the helical phase
• Domain wall motion at low current density in a synthetic antiferromagnet nanowire
• Reconfigurable magnetic domain wall pinning at the nano-scale using vortex-generated magnetic fields