Interfacial Dzyaloshinskii-Moriya interaction in epitaxial W/Co/Pt multilayers

TL;DR

This study investigates the Dzyaloshinskii-Moriya interaction in epitaxial W/Co/Pt multilayers, revealing high DMI values due to high crystalline quality and interfacial atomic contributions, supported by experimental and theoretical analysis.

Contribution

It demonstrates that epitaxial growth yields higher DMI in multilayers, with precise measurements and modeling confirming the interfacial atomic contributions to DMI strength.

Findings

DMI coefficient exceeds 2 mJ/m2 in epitaxial multilayers

Highest DMI value D_eff = 2.64 mJ/m2 observed for N=10 layers

Experimental results align with micromagnetic and DFT modeling

Abstract

Dzyaloshinskii-Moriya interaction (DMI) manifesting in asymmetric layered ferromagnetic films gives rise to non-colinear spin structures stabilizing magnetization configurations with nontrivial topology. In this work magnetization reversal, domain structure, and strength of DMI are related with the structure of W/Co/Pt multilayers grown by molecular beam epitaxy. Applied growth method enables fabrication of layered systems with higher crystalline quality than commonly applied sputtering techniques. As a result, a high value of D coefficient was determined from the aligned magnetic domain stripe structure, substantially exceeding 2 mJ/m2. The highest value of DMI value D$_{eff}$ = 2.64mj/m2 and strength of surface DMI parameter DS = 1.83pJ/m for N=10 has been observed. Experimental results coincide precisely with those obtained from structure based micromagnetic modelling and density functional theory calculations performed for well-defined layered stacks. This high value of DMI strength originates from dominating contributions of the interfacial atomic Co layers and additive character from both interface types.