Spin-Orbit Optical Hall Effect

AbstractThe orbital Hall effect describes the generation of the orbital current flowing in a perpendicular direction to an external electric field, analogous to the spin Hall effect. As the orbital current carries the angular momentum as the spin current does, injection of the orbital current into a ferromagnet can result in torque on the magnetization, which provides a way to detect the orbital Hall effect. With this motivation, we examine the current-induced spin-orbit torques in various ferromagnet/heavy metal bilayers by theory and experiment. Analysis of the magnetic torque reveals the presence of the contribution from the orbital Hall effect in the heavy metal, which competes with the contribution from the spin Hall effect. In particular, we find that the net torque in Ni/Ta bilayers is opposite in sign to the spin Hall theory prediction but instead consistent with the orbital Hall theory, which unambiguously confirms the orbital torque generated by the orbital Hall effect. Our finding opens a possibility of utilizing the orbital current for spintronic device applications, and it will invigorate researches on spin-orbit-coupled phenomena based on orbital engineering.

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Giant forward-scattering asymmetry and anomalous tunnel Hall effect at spin-orbit-split and exchange-split interfaces

Physical Review B ◽

10.1103/physrevb.92.060403 ◽

2015 ◽

Vol 92 (6) ◽

Cited By ~ 8

Author(s):

T. Huong Dang ◽

H. Jaffrès ◽

T. L. Hoai Nguyen ◽

H.-J. Drouhin

Keyword(s):

Hall Effect ◽

Forward Scattering ◽

Spin Orbit

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Experimental Observation of the Spin-Hall Effect in a Two-Dimensional Spin-Orbit Coupled Semiconductor System

Physical Review Letters ◽

10.1103/physrevlett.94.047204 ◽

2005 ◽

Vol 94 (4) ◽

Cited By ~ 1106

Author(s):

J. Wunderlich ◽

B. Kaestner ◽

J. Sinova ◽

T. Jungwirth

Keyword(s):

Hall Effect ◽

Experimental Observation ◽

Spin Hall Effect ◽

Spin Orbit ◽

Two Dimensional ◽

Semiconductor System ◽

Coupled Semiconductor

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Inactivation of damping-like torque in Tb-Gd-Fe film on Ta layer

Japanese Journal of Applied Physics ◽

10.35848/1347-4065/ac3fcb ◽

2021 ◽

Author(s):

Yuichiro Kurokawa ◽

Masahiro Itoh ◽

Masakazu Wakae ◽

Masahiro Fujimoto ◽

Uraku Kamihoki ◽

...

Keyword(s):

Rare Earth ◽

Transition Metal ◽

Hall Effect ◽

Effective Field ◽

Spin Hall Effect ◽

Spin Orbit

Abstract Recently, bulk spin orbit torques (SOTs) in transition metal-rare earth (TM-RE) ferrimagnets have been reported. In this study, to investigate bulk SOTs, we observed the current-induced effective field mediated by a damping-like torque (DLT), which is one of the components of SOTs, using TM-RE ferrimagnetic Tb x (Gd32Fe68)100-x films with a Ta layer. The DLT efficiency ξ DL was inactivated by increasing the Tb composition x to be greater than 8, suggesting that the DLT was induced by the bulk SOTs of Tb x (Gd32Fe68)100-x as well as the spin Hall effect in the Ta. However, from the DLT measurement using a Tb8(Gd32Fe68)92 layer sandwiched between Ru layers, where Ru has a negligibly small DLT, ξ DL was almost zero. This indicates that the inactivation of DLT cannot simply be explained by the bulk SOTs of Tb x (Gd32Fe68)100-x . However, we expect that this finding will provide meaningful insights for controlling magnetization using current.

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