Fully Spin-Transparent Magnetic Interfaces Enabled by the Insertion of a Thin Paramagnetic NiO Layer
Author(s): Zhu, LJ (Zhu, Lijun); Au, LJ (Au, Lujun); Buhrman, RA (Buhrman, Robert A.)
Source: PHYSICAL REVIEW LETTERS Volume: 126 Issue: 10 Article Number: 107204 DOI: 10.1103/PhysRevLett.126.107204 Published: MAR 12 2021
Abstract: Spin backflow and spin-memory loss have been well established to considerably lower the interfacial spin transmissivity of metallic magnetic interfaces and thus the energy efficiency of spin-orbit torque technologies. Here, we report that spin backflow and spin-memory loss at Pt-based heavy metal-ferromagnet interfaces can be effectively eliminated by inserting an insulating paramagnetic NiO layer of optimum thickness. The latter enables the thermal magnon-mediated essentially unity spin-current transmission at room temperature due to considerably enhanced effective spin-mixing conductance of the interface. As a result, we obtain damping like spin-orbit torque efficiency per unit current density of up to 0.8 as detected by the standard technology ferromagnet FeCoB and others, which reaches the expected upper-limit spin Hall ratio of Pt. We establish that Pt/NiO and Pt-Hf/NiO are two energy-efficient, integration-friendly, and high-endurance spin-current generators that provide >100 times greater energy efficiency than sputter-deposited topological insulators BiSb and BiSe. Our finding will benefit spinorbitronic research and advance spin-torque technologies.
Accession Number: WOS:000652824700019
PubMed ID: 33784166
Author Identifiers:
Author Web of Science ResearcherID ORCID Number
Zhu, Lijun AAK-6127-2021 0000-0001-8750-3847
ISSN: 0031-9007
eISSN: 1079-7114
Full Text: https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.126.107204