Spin dynamics of hard-soft magnetic multi-layer systems: Effect of Exchange, Dipolar and Dzyaloshinski-Moriya interactions

TL;DR

This paper explores how exchange, dipolar, and Dzyaloshinski-Moriya interactions influence the spin dynamics in layered magnetic systems, revealing subtle effects that offer additional control over spin configurations.

Contribution

It provides a comparative analysis of exchange, dipolar, and Dzyaloshinski-Moriya interactions on spin configurations in multi-layer magnetic systems.

Findings

Dipolar and Dzyaloshinski-Moriya interactions cause slight deviations in spin orientation.

Exchange coupling has a dominant effect on magnetization profiles.

Additional degrees of freedom are available for spin configuration tuning.

Abstract

We investigate the effect of coupling (intensity and nature), applied field, and anisotropy on the spin dynamics of a multi-layer system composed of a hard magnetic slab coupled to a soft magnetic slab through a nonmagnetic spacer. The soft slab is modeled as a stack of several atomic layers while the hard layer, of a different material, is either considered as a pinned macroscopic magnetic moment or as an atomic multi-layer system. We compute the magnetization profile and hysteresis loop of the multi-layer system by solving the Landau-Lifshitz equations for the net magnetic moment of each (atomic) layer. We study the competition between the intra-layer anisotropy and exchange interaction, applied magnetic field, and the inter-slab exchange, dipolar or Dzyaloshinski-Moriya interaction. Comparing the effects on the magnetization profile of the three couplings shows that despite the strong effect of the exchange coupling, the dipolar and Dzyaloshinski-Moriya interactions induce a slight (but non negligible) deviation in either the polar or azimuthal direction thus providing more degrees of freedom for adjusting the spin configuration in the multi-layer system.