Role of the chiral spin configuration in field-free spin-orbit torque-induced magnetization switching by a locally injected spin current

• Published in: arXiv.org 2022-03
• Main Authors: An, Suhyeok, Seo, Hyeong-Joo, Baek, Eunchong, Lee, Soobeom, Chun-Yeol You
• Format: Article
• Language: English
• Subjects: Asymmetry; Chirality; Configurations; Ferromagnetism; Heavy metals; Magnetic anisotropy; Magnetic switching; Magnetism; Magnetization; Spintronics; Torque
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.2203.14429

For deterministic magnetization switching by spin-orbit torque (SOT) in a perpendicular magnetic anisotropy system, an additional in-plane direction magnetic field is essential for deterministic switching by breaking the magnetization symmetry. Realizing chirality in a magnetic ordering system can be one approach for achieving asymmetry in the lateral direction for field-free magnetization switching. However, systematic analysis of the influence of the chiral spin system on deterministic switching is still scarce. In this report, the achievement of field-free SOT-induced magnetization switching by using a chiral spin configuration is investigated by experiments and micromagnetic simulations. We designed a system in which only part of the ferromagnetic layer overlaps with the heavy metal layer in the Pt/Co/MgO structure. Therefore, a spin current is exerted only on a local area of the ferromagnetic layer, which results in a Néel-type chiral spin configuration. The induced chiral spin configuration can be stabilized (or destabilized) depending on the sign of the interfacial Dzyaloshinskii-Moriya interaction of the system. The stabilized spin configuration plays a crucial role in the deterministic switching in zero field. We expect our findings to widen the perspective on chirality-based all-electrical SOT device fabrication.