Impact of surface strain on the spin dynamics of deposited Co nanowires

Abstract

Tailoring the magnetic properties at atomic-scale is essential in the engineering of modern spintronics devices. One of the main concerns in the novel nanostructured materials design is the decrease of the paid energy in the way of functioning, but allowing to switch between different magnetic states with a relative low-cost energy at the same time. Magnetic anisotropy (MA) energy defines the stability of a spin in the preferred direction and is a fundamental variable in magnetization switching processes. Transition-metal wires are known to develop large, stable spin and orbital magnetic moments together with MA energies that are orders of magnitude larger than in the corresponding solids. Different ways of controlling the MA have been exploited such as alloying, surface charging, and external electrical fields. Here we investigate from a first-principle approach together with dynamic calculations, the surface strain driven mechanism to tune the magnetic properties of deposited nanowires. We consider as a prototype system, the monoatomic Co wires deposited on strained Pt(111) and Au(111) surfaces. Our first-principles calculations reveal a monotonic increase/decrease of MA energy under compressive/tensile strain in supported Co wire. Moreover, the spin dynamics studies based on solving the Landau-Lifshitz-Gilbert equation show that the induced surface-strain leads to a substantial decrease of the required external magnetic field magnitude for magnetization switching in Co wire.

Oxygen-Mediated Superexchange Interactions and Their Impact on the Structural Stability, Magnetic Order, and Magnetocrystalline Anisotropy of One-Dimensional Co-Oxide Chains on Rh(553) Step-Surfaces

“…The nature of such couplings and their contribution to the magnetization direction have been discussed everywhere. See refs , , and , for instance.…”

Ferromagnetism in Monatomic Chains: Spin-Dependent Bandwidth Narrowing/Broadening

“…These NWs show enhanced magnetism, as compared to their bulk (3D) state, and quantized conductance. They are predicted to be technologically useful for spintronics-based devices. , Various studies have been carried out on 1D monatomic chains , including transition elements of 3d series, ,,− 4d series, , 5d series, ,,, and alkali metals. − It was found that Pt nanowires exhibit Hund’s rule magnetism, and the magnetic moment increases upon stretching; however, in the bulk state Pt does not show magnetism . Delin et al explored the spin dynamics of atomically thin platinum wires based on first-principles calculations.…”