Magnetization statics and dynamics in (Ir/Co/Pt)$_6$ multilayers with Dzyaloshinskii-Moriya interaction

TL;DR

This study investigates the static and dynamic magnetic properties of (Ir/Co/Pt)$_6$ multilayers with interfacial Dzyaloshinskii-Moriya interaction, revealing complex domain structures and quantifying the interaction's strength through experimental and simulation methods.

Contribution

The paper provides a comprehensive analysis of IDMI effects in multilayers, combining experimental techniques and micromagnetic simulations to quantify the interaction and understand domain behavior.

Findings

Existence of weak stripe domain structures with in-plane and out-of-plane magnetization components.

Quantitative evaluation of IDMI energy density using Brillouin light scattering.

Hysteresis observed in frequency differences related to IDMI under magnetic field variation.

Abstract

Magnetic multilayers of (Ir/Co/Pt)$_6$ with interfacial Dzyaloshinskii-Moriya interaction (IDMI) were deposited by magnetron sputtering with Co thickness $d=1.8$ nm. Exploiting magneto-optical Kerr effect in longitudinal mode microscopy, magnetic force microscopy, and vibrating sample magnetometry, the magnetic field-driven evolution of domain structures and magnetization hysteresis loops have been studied. The existence of weak stripe domains structure was deduced -- tens micrometers size domains with in-plane "core" magnetization modulated by hundred of nanometers domains with out-of-plane magnetization. Micromagnetic simulations interpreted such magnetization distribution. Quantitative evaluation of IDMI was carried out using Brillouin light scattering (BLS) spectroscopy as the difference between Stokes and anti-Stokes peak frequencies $\Delta f$. Due to the additive nature of IDMI, the asymmetric combination of Ir and Pt covers led to large values of effective IDMI energy density $D_\mathrm{eff}$. It was found that Stokes and anti-Stokes frequencies as well as $\Delta f$, measured as a function of in-plane applied magnetic field, show hysteresis. These results are explained under the consideration of the influence of IDMI on the dynamics of the in-plane magnetized "core" with weak stripe domains.