Nonreciprocal spin-wave dynamics in Pt/Co/W/Co/Pt multilayers

TL;DR

This study investigates nonreciprocal spin-wave behavior in Pt/Co/W multilayers, revealing how layer order and magnetic anisotropy influence spin-wave dispersion, with implications for developing advanced magnonic devices.

Contribution

It demonstrates the impact of layer deposition order and magnetic anisotropy on nonreciprocal spin-wave dispersion in multilayer systems, supported by experiments and theoretical analysis.

Findings

Nonreciprocal dispersion relation induced by Dzyaloshinskii-Moriya interaction.

Layer order significantly affects magnetic parameters and spin-wave modes.

Differences in magnetic anisotropy alter interlayer interactions and dispersion relations.

Abstract

We present a detailed study of the spin-wave dynamics in single Pt/Co/W and double Pt/Co/W/Co/Pt ferromagnetic layer systems. The dispersion of spin waves was measured by wavevector-resolved Brillouin light scattering spectroscopy while the in-plane and out-of-plane magnetization curves were measured by alternating gradient field magnetometry. The interfacial Dzyaloshinskii-Moriya interaction induced nonreciprocal dispersion relation was demonstrated for both single and double ferromagnetic layers and explicated by numerical simulations and theoretical formulas. The results indicate the crucial role of the order of layers deposition on the magnetic parameters. A significant difference between the perpendicular magnetic anisotropy constant in double ferromagnetic layer systems conduces to the decline of the interlayer interactions and different dispersion relations for the spin-wave modes. Our study provides a significant contribution to the realization of the multifunctional nonreciprocal magnonic devices based on ultrathin ferromagnetic/heavy-metal layer systems.