Abstract:Spin current generation through the spin-orbit interaction in non-magnetic materials lies at the heart of spintronics. When the generated spin current is injected to a ferromagnet, it produces spin-orbit torque and manipulates magnetization efficiently. Optically generated spin currents are expected to be superior to their electrical counterparts in terms of the manipulation speed. Here we report optical spin-orbit torques in heavy metal/ferromagnet heterostructures. The strong spin-orbit coupling of heavy met… Show more
“…Note that the giant amplitude of inverse and direct Rashba-Edelstein effect in oxide heterostructures of SrTiO 3 and LaAlO 3 /SrTiO 3 formed quasi 2D electron gas (2DEG) system also provide significant charge-spin interconversions ( Noël et al., 2020 ), holding the promise to pave the way from oxide spin-orbitronics prospect toward low-power electrical control of magnetizations. In addition, the frontier researches on spin-orbitronics could inspire innovations in other spintronic devices, e.g., the newly reported optical spin-orbit torque (OSOT) devices with an optical means for magnetization manipulation in FM layer ( Choi et al., 2020 ), and the magnonic devices where significant discoveries in the detection and the manipulation (see Figure 6 D) of magnetization via spin waves have been recently presented ( Han et al., 2019 ; Wang et al., 2019b ; Liu et al., 2019a ). Figure 6 Representative Reprinted Works Reported on Spin-Orbitronics in Exotic Magnetic Materials beyond the Ferromagnets (A) Electric switching of antiferromagnet.…”
Summary
Science, engineering, and medicine ultimately demand fast information processing with ultra-low power consumption. The recently developed spin-orbit torque (SOT)-induced magnetization switching paradigm has been fueling opportunities for spin-orbitronic devices, i.e., enabling SOT memory and logic devices at sub-nano second and sub-picojoule regimes. Importantly, spin-orbitronic devices are intrinsic of nonvolatility, anti-radiation, unlimited endurance, excellent stability, and CMOS compatibility, toward emerging applications, e.g., processing in-memory, neuromorphic computing, probabilistic computing, and 3D magnetic random access memory. Nevertheless, the cutting-edge SOT-based devices and application remain at a premature stage owing to the lack of scalable methodology on the field-free SOT switching. Moreover, spin-orbitronics poises as an interdisciplinary field to be driven by goals of both fundamental discoveries and application innovations, to open fascinating new paths for basic research and new line of technologies. In this perspective, the specific challenges and opportunities are summarized to exert momentum on both research and eventual applications of spin-orbitronic devices.
“…Note that the giant amplitude of inverse and direct Rashba-Edelstein effect in oxide heterostructures of SrTiO 3 and LaAlO 3 /SrTiO 3 formed quasi 2D electron gas (2DEG) system also provide significant charge-spin interconversions ( Noël et al., 2020 ), holding the promise to pave the way from oxide spin-orbitronics prospect toward low-power electrical control of magnetizations. In addition, the frontier researches on spin-orbitronics could inspire innovations in other spintronic devices, e.g., the newly reported optical spin-orbit torque (OSOT) devices with an optical means for magnetization manipulation in FM layer ( Choi et al., 2020 ), and the magnonic devices where significant discoveries in the detection and the manipulation (see Figure 6 D) of magnetization via spin waves have been recently presented ( Han et al., 2019 ; Wang et al., 2019b ; Liu et al., 2019a ). Figure 6 Representative Reprinted Works Reported on Spin-Orbitronics in Exotic Magnetic Materials beyond the Ferromagnets (A) Electric switching of antiferromagnet.…”
Summary
Science, engineering, and medicine ultimately demand fast information processing with ultra-low power consumption. The recently developed spin-orbit torque (SOT)-induced magnetization switching paradigm has been fueling opportunities for spin-orbitronic devices, i.e., enabling SOT memory and logic devices at sub-nano second and sub-picojoule regimes. Importantly, spin-orbitronic devices are intrinsic of nonvolatility, anti-radiation, unlimited endurance, excellent stability, and CMOS compatibility, toward emerging applications, e.g., processing in-memory, neuromorphic computing, probabilistic computing, and 3D magnetic random access memory. Nevertheless, the cutting-edge SOT-based devices and application remain at a premature stage owing to the lack of scalable methodology on the field-free SOT switching. Moreover, spin-orbitronics poises as an interdisciplinary field to be driven by goals of both fundamental discoveries and application innovations, to open fascinating new paths for basic research and new line of technologies. In this perspective, the specific challenges and opportunities are summarized to exert momentum on both research and eventual applications of spin-orbitronic devices.
“…In contrast to the accumulative magnetization switching induced by magnetic circular dichroism, a recent experimental study observed that magnetization reversal is also induced by a single circularly polarized laser pulse [10]. In addition, magnetization precession dynamics induced by optical helicity in a metallic thin film magnet was observed [18,19]. The torque on magnetization induced by optical helicity in metallic heterostructures can generate a helicity-dependent terahertz emission [20,21], in which the terahertz photocurrent is produced due to the inversion symmetry breaking of the thin film structure.…”
Section: Introductionmentioning
confidence: 99%
“…In the initial observations of optical spin torque in metallic thin film magnets, optical helicity-induced magnetization precession was mainly explained by the inverse Faraday effect in ferromagnetic metals [18], in which the optical spin torque has a field-like form, m × s, where m and s are the magnetization and spin direction pointing along the wave vector of the light, i.e., s ∝ E × E ⋆ . However, the recent observations of the optical helicityinduced magnetization precession in Co/Pt bilayer can be explained using spin-transfer mechanism as follows [19]. The spin s generated by the optical helicity in the Pt layer was due to the optical orientation, and it transfers its angular momentum to an adjacent Co layer via the spintransfer torque effect.…”
Section: Introductionmentioning
confidence: 99%
“…The study by Choi et al [19] have studied the effect of circularly polarized light with different thickness of Co and Pt. Then, they discussed the thickness dependences in terms of light absorption and optical orientation in nonmagnetic heavy metal Pt.…”
The manipulation of magnetization in a metallic ferromagnet by using optical helicity has been much attracted attention for future opto-spintronic devices. The optical helicity–induced torques on the magnetization, optical spin torque, have been observed in ferromagnetic thin films recently. However, the interfacial effect of the optical spin torque in ferromagnet/nonmagnetic heavy metal heterostructures have not been addressed so far, which are widely utilized to efficiently control magnetization via electrical means. Here, we studied optical spin torque vectors in the ferromagnet/nonmagnetic heavy metal heterostructures and observed that in-plane field-like optical spin torque was significantly increased with decreasing ferromagnetic layer thicknesses. The interfacial field-like optical spin torque was explained by the optical Rashba–Edelstein effect caused by the structural inversion symmetry breaking. This work will aid in the efficient optical manipulation of thin film nanomagnets using optical helicity.
“…The spin currents are generated by the ultrafast demagnetization of a ferromagnet 12 : a ferromagnet is exposed to a femtosecond laser pulse; if the ferromagnet is in contact with a nonmagnetic metal, a spin current is injected into the non-magnet 13 – 15 . Another way of generating femtosecond spin current pulses is by optical pumping of a heavy metal with circularly polarized light 16 .…”
The ultrafast demagnetization effect allows for the generation of femtosecond spin current pulses, which is expected to extend the fields of spin transport and spintronics to the femtosecond time domain. thus far, directly observing the spin polarization induced by spin injection on the femtosecond time scale has not been possible. Herein, we present time-and spin-resolved photoemission results of spin injection from a laser-excited ferromagnet into a thin gold layer. The injected spin polarization is aligned along the magnetization direction of the underlying ferromagnet. Its decay time depends on the thickness of the gold layer, indicating that transport as well as storage of spins are relevant. this capacitive aspect of spin transport may limit the speed of future spintronic devices.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
