High Spin Hall Conductivity Induced by Ferromagnet and Interface

Abstract

Spin-orbit-torque (SOT) offers a highly attractive perspective for manipulating magnetization dynamics in magnetic nanostructures. SOT is been observed and studied in various systems. However, limited by the efficiency, SOT-induced switching of the ultrahard ferromagnet is still extremely difficult and a further improvement in efficiency is requested. Here, the SOT is reported in chemically disordered soft Fe 0.5 Pt 0.5 and Pt/Fe 0.5 Pt 0.5 bilayers. Due to the magnetization-strengthened spin Hall effect, the damping-like torque efficiency and spin Hall conductivity (SHC) in Fe 0.5 Pt 0.5 reach 1.11 and 1.08 × 10 6 ℏ/2e Ω −1 m −1 respectively, much higher than those in conventional materials. Furthermore, the Pt/Fe 0.5 Pt 0.5 interface enhances SHC to a total of 2.93 × 10 6 ℏ/2e Ω −1 m −1 due to the interfacial symmetry breaking. This system can be used to partially switch the magnetization of ultra-hard exchange-spring system with a switching field of 1T by applying a relatively low current. This finding will push forward the development of SOT devices with ultrahigh-density and low-power consumption.

Spintronic Heterostructures for Artificial Intelligence: A Materials Perspective

“…As another material option, Li et al studied the SOT‐driven magnetization switching in FePt ferromagnet and observed the magnetization switching at J = ≈7.3 × 10 11 A m −2 (and H x = 1500 Oe). [ 181 ] A higher charge‐to‐spin current conversion efficiency of 1.11 was observed in this study (corresponding resistivity of ≈100–150 45 μΩ cm). Meanwhile, Tao et al also reported the field‐free magnetization switching in the L 1 0 ‐FePt system at a similar current density of ≈3 × 10 11 A m −2 .…”

Enhanced spin–orbit torque and field-free switching in Au/TMDs/Ni hybrid structures

“…After several pulses, no degeneration in R H is observed, so the influence of Joule heat in switching can be negligible. 57 As the amplitude of the current pulse changes, R H shows steady multiple values, which proves that the characteristics of synapses can be simulated by setting different current sequences. 5,58 These results indicate the great potential for applications of similar structures in high-density magnetic storage or memristors for neuromorphic computing.…”

Sliding Ferroelectricity Engineered Coupling between Spin Hall Effect and Layertronics in 2D Lattice

“…Meanwhile, arising from the interplay between SHE and novel physics, many fascinating phenomena are observed, − and recent years have witnessed the rapid development of this field. For example, combined with the established physics of the dissipationless quantum Hall effect, the intrinsic SHE leads to the prediction and subsequent experimental verification of the quantum spin Hall effect (QSHE) in 2D systems, − initiating the research field of topological insulators.…”