Anomalous Hall effect at a 
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 interface

Hayashi, Hiroki; Asami, Akio; Ando, Kotoji

doi:10.1103/physrevb.100.214415

Cited by 11 publications

(2 citation statements)

References 46 publications

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“…This result is reminiscent of the scaling of the anomalous Hall conductivity. Previous studies have shown that the oxygen incorporation in Pt allows to explore SOC phenomena at ferromagnetic-metal/PtO x interfaces 17,18,[31][32][33] . Our result shows that the oxidation-level tuning of PtO x also offers a promising way to explore the phenomena arising from the bulk SOC in spintronic devices.…”

Section: Transport Measurementmentioning

confidence: 99%

Observation of the crossover between metallic and insulating regimes of the spin Hall effect

Moriya

Musha

Haku

et al. 2021

Preprint

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The physics of the anomalous and spin Hall effects is one of the most intriguing aspects of condensed matter physics. An important finding from a large collection of experimental and theoretical results is the universal scaling of the anomalous or spin Hall conductivity with the electric conductivity. This scaling has been successfully described by the intrinsic Berry curvature and extrinsic scattering mechanisms for metallic systems, revealing the topological nature of these effects. In contrast, the underlying physics in the opposite limit, the disordered insulating regime, is still unclear. In particular, it remains a major challenge to explore the spin Hall effect in the insulating regime. Here, we report the observation of the crossover between the metallic and insulating regimes of the spin Hall effect. The result demonstrates an important correspondence between the spin and anomalous Hall effects, which provides essential information for the fundamental understanding of spin transport.

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Section: Transport Measurementmentioning

confidence: 99%

Observation of the crossover between metallic and insulating regimes of the spin Hall effect

Moriya

Musha

Haku

et al. 2021

Preprint

Self Cite

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“…Conventional SOT devices exploit this accumulation of spin for magnetization switching by interfacing the HM with a ferromagnetic (FM) layer, which allows the accumulated spins to cross the HM/FM interface and interact with the FM magnetic moments through angular momentum transfer. Aside from such mechanisms, it is also reported that scattering can occur at seed layer/HM or FM/capping interfaces. − As such, the spin density of states within an HM layer interfacing with the seed layer can be brought out of balance from purely SHE through spin scattering or spin reflection, which in turn may be used to modulate the spin accumulation at the HM/FM interface. As discussed in previous works on Pt/Co SOT heterostructures, the spin generation along an HM Pt track with a thickness of d can be described by J s ( d ) = J s (∞)[1 – sech( d /λ s )] based on the spin drift-diffusion theory, where J s (∞) is the spin current at infinite Pt thickness and λ s is the spin diffusion length. − Those works mainly dealt with the Pt/Co interface and assumed that no spin current penetrates out of the X/Pt interface, where X is the non-FM seed layer interfacing Pt.…”

Section: Introductionmentioning

confidence: 99%

Spin Reflection-Induced Field-Free Magnetization Switching in Perpendicularly Magnetized MgO/Pt/Co Heterostructures

Jin

Lim

Poh

et al. 2022

ACS Appl. Mater. Interfaces

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Field-free magnetization switching is critical towards practical, integrated spin-orbit torque (SOT)-driven magnetic random-access memory with perpendicular magnetic anisotropy. Our work proposes a technique to modulate the spin reflection and spin density of states within a heavy-metal Pt through interfacing with a dielectric MgO layer. We demonstrate tunability of the effective out-of-plane spin torque acting on the ferromagnetic Co layer, enabling current-induced SOT magnetization switching without the assistance of an external magnetic field. The influence of the MgO layer thickness on effective SOT efficiency shows saturation at 4 nm, while up to 80% of field-free magnetization switching ratio is achieved with the MgO between 5 and 8 nm. We analyze and attribute the complex interaction to spin reflection at the dielectric/heavy metal interface and spin scattering within the dielectric medium due to interfacial electric fields. Further, through substituting the dielectric with Ti or Pt, we confirm that the MgO layer is indeed responsible for the observed field-free magnetization switching mechanism.

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Spin‐Torque Manipulation for Hydrogen Sensing

Haku

Kageyama

et al. 2020

Adv Funct Materials

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External manipulation of spin‐orbit torques (SOTs) promises not only energy‐efficient spin‐orbitronic devices but also versatile applications of spin‐based technologies in diverse fields. However, the external electric‐field control, widely used in semiconductor spintronics, is known to be ineffective in conventional metallic spin‐orbitronic devices due to the very short screening length. Here, an alternative approach to control the SOTs by using gases is shown. It is demonstrated that the spin‐torque generation efficiency of a Pd/Ni81Fe19 bilayer can be reversibly manipulated by the absorption and desorption of H2 gas, which appears concomitantly with the change of the electrical resistance. It is found that compared with the change of the Pd resistance induced by the H2 absorption, the change of the spin‐torque generation efficiency is almost an order of magnitude larger. This result provides a new method to externally manipulate the SOTs and paves a way for developing more sensitive hydrogen sensors based on the spin‐orbitronic technology.

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Anomalous Hall effect at a PtOx/Co interface

Cited by 11 publications

References 46 publications

Observation of the crossover between metallic and insulating regimes of the spin Hall effect

Observation of the crossover between metallic and insulating regimes of the spin Hall effect

Spin Reflection-Induced Field-Free Magnetization Switching in Perpendicularly Magnetized MgO/Pt/Co Heterostructures

Spin‐Torque Manipulation for Hydrogen Sensing

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