Abstract

Owing to the unique features of low Gilbert damping, long spin-diffusion lengths, and zero Ohmic losses, magnetic insulators are promising candidate materials for next-generation spintronic applications. However, due to the localized magnetic moments and the complex metal-oxide interface between magnetic insulators and heavy metals, spin-functional Dzyaloshinskii-Moriya interactions or spin Hall and Edelstein effects are weak, which diminishes the performance of these typical building blocks for spintronic devices. Herein, the exchange coupling between metallic and insulating magnets is exploited for efficient electrical manipulation of heavy metal/magnetic insulator heterostructures. By inserting a thin Co layer, the spin-orbit torque efficiency is enhanced by more than 20 times, which significantly reduces the switching current density. Moreover, field-free current-induced magnetization switching caused by a symmetry-breaking non-collinear magnetic texture is demonstrated. This work launches magnetic insulators as an alternative platform for low-power spintronic devices. Engineering the magnetic coupling plays a crucial role in determining the functionalities of spintronic devices. The exchange coupling between metallic and insulating magnets is exploited for efficient electrical manipulation of magnetic insulators. By inserting thin Co layers, the spin-orbit torque efficiency is enhanced by more than 20 times and the field-free current-induced magnetization switching is demonstrated.image (c) 2024 WILEY-VCH GmbH