The Experts below are selected from a list of 31629 Experts worldwide ranked by ideXlab platform
Kohei Hamaya - One of the best experts on this subject based on the ideXlab platform.
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Pure Spin current transport in a SiGe alloy
Applied Physics Express, 2018Co-Authors: Takahiro Naito, Shinya Yamada, Michihiro Yamada, Makoto Tsukahara, Kentarou Sawano, Kohei HamayaAbstract:Using four-terminal nonlocal magnetoresistance measurements in lateral Spin-valve devices with Si0.1Ge0.9, we study Pure Spin current transport in a degenerate SiGe alloy (n ~ 5.0 × 1018 cm−3). Clear nonlocal Spin-valve signals and Hanle effect curves, indicating generation, transport, and detection of Pure Spin currents, are observed. The Spin diffusion length and Spin lifetime of the Si0.1Ge0.9 layer at low temperatures are reliably estimated to be ~0.5 µm and ~0.2 ns, respectively. This study demonstrates the possibility of exploring physics and developing Spintronic applications using SiGe alloys.
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Room-temperature generation of giant Pure Spin currents using epitaxial Co_2FeSi Spin injectors
NPG Asia Materials, 2012Co-Authors: Takashi Kimura, Masanobu Miyao, Shinya Yamada, Naoki Hashimoto, Kohei HamayaAbstract:Spintronics: Current generationTakashi Kimura, Kohei Hamaya and co-workers have generated large Pure Spin currents at room temperature, with high efficiency. Spintronic devices, which use the Spin of electrons as well as their charge, promise to be faster and less power-consuming than traditional charge-based electronic ones. A Pure Spin current — a flow that is not accompanied by charge current — seems to be a promising way to write information for such devices. However, although ‘Spin injectors’ capable of creating such currents have been developed, their efficiency has generally remained too low for practical applications. Now, Kimura, Hamaya and colleagues have significantly improved this efficiency by using a highly ordered cobalt-iron-silicon ‘Heusler’ compound with high Spin polarization. These findings highlight the potential of Heusler compounds as Spin injectors, and move the construction of functional Spintronic devices one step forward.Heusler compound Spin injector with a high Spin polarization dramatically improves the generation efficiency of the Pure Spin current compared with a conventional ferromagnetic metal.AbstractThe generation, manipulation and detection of a Pure Spin current (i.e., the flow of Spin angular momentum without a charge current) are prospective approaches for realizing next-generation Spintronic devices with ultra-low electric power consumption. Conventional ferromagnetic electrodes such as Co and NiFe have been utilized as Spin injectors to generate Pure Spin currents in nonmagnetic channels. However, the generation efficiency of Pure Spin currents is extremely low at room temperature, giving rise to a serious obstacle for device applications. Here we demonstrate the generation of giant Pure Spin currents at room temperature in lateral Spin valve devices with a highly ordered Heusler-compound Co_2FeSi (CFS) Spin injector. The generation efficiency of Pure Spin currents from the CFS Spin injectors is 10 times greater than that of the NiFe injectors, indicating that Heusler compound Spin injectors with high Spin polarization enable us to materialize a high-performance lateral Spin device. The present study is a technological jump in Spintronics, and indicates the great potential of ferromagnetic Heusler compounds with half metallicity for generating Pure Spin currents.
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Room-temperature generation of giant Pure Spin currents using epitaxial Co_2FeSi Spin injectors
NPG Asia Materials, 2012Co-Authors: Takashi Kimura, Masanobu Miyao, Shinya Yamada, Naoki Hashimoto, Kohei HamayaAbstract:The generation, manipulation and detection of a Pure Spin current (i.e., the flow of Spin angular momentum without a charge current) are prospective approaches for realizing next-generation Spintronic devices with ultra-low electric power consumption. Conventional ferromagnetic electrodes such as Co and NiFe have been utilized as Spin injectors to generate Pure Spin currents in nonmagnetic channels. However, the generation efficiency of Pure Spin currents is extremely low at room temperature, giving rise to a serious obstacle for device applications. Here we demonstrate the generation of giant Pure Spin currents at room temperature in lateral Spin valve devices with a highly ordered Heusler-compound Co_2FeSi (CFS) Spin injector. The generation efficiency of Pure Spin currents from the CFS Spin injectors is 10 times greater than that of the NiFe injectors, indicating that Heusler compound Spin injectors with high Spin polarization enable us to materialize a high-performance lateral Spin device. The present study is a technological jump in Spintronics, and indicates the great potential of ferromagnetic Heusler compounds with half metallicity for generating Pure Spin currents. Takashi Kimura, Kohei Hamaya and co-workers have generated large Pure Spin currents at room temperature, with high efficiency. Spintronic devices, which use the Spin of electrons as well as their charge, promise to be faster and less power-consuming than traditional charge-based electronic ones. A Pure Spin current — a flow that is not accompanied by charge current — seems to be a promising way to write information for such devices. However, although ‘Spin injectors’ capable of creating such currents have been developed, their efficiency has generally remained too low for practical applications. Now, Kimura, Hamaya and colleagues have significantly improved this efficiency by using a highly ordered cobalt-iron-silicon ‘Heusler’ compound with high Spin polarization. These findings highlight the potential of Heusler compounds as Spin injectors, and move the construction of functional Spintronic devices one step forward. Heusler compound Spin injector with a high Spin polarization dramatically improves the generation efficiency of the Pure Spin current compared with a conventional ferromagnetic metal.
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room temperature generation of giant Pure Spin currents using epitaxial co2fesi Spin injectors
Npg Asia Materials, 2012Co-Authors: Takashi Kimura, Masanobu Miyao, Kohei Hamaya, Shinya Yamada, Naoki HashimotoAbstract:The generation, manipulation and detection of a Pure Spin current (i.e., the flow of Spin angular momentum without a charge current) are prospective approaches for realizing next-generation Spintronic devices with ultra-low electric power consumption. Conventional ferromagnetic electrodes such as Co and NiFe have been utilized as Spin injectors to generate Pure Spin currents in nonmagnetic channels. However, the generation efficiency of Pure Spin currents is extremely low at room temperature, giving rise to a serious obstacle for device applications. Here we demonstrate the generation of giant Pure Spin currents at room temperature in lateral Spin valve devices with a highly ordered Heusler-compound Co2FeSi (CFS) Spin injector. The generation efficiency of Pure Spin currents from the CFS Spin injectors is 10 times greater than that of the NiFe injectors, indicating that Heusler compound Spin injectors with high Spin polarization enable us to materialize a high-performance lateral Spin device. The present study is a technological jump in Spintronics, and indicates the great potential of ferromagnetic Heusler compounds with half metallicity for generating Pure Spin currents. Takashi Kimura, Kohei Hamaya and co-workers have generated large Pure Spin currents at room temperature, with high efficiency. Spintronic devices, which use the Spin of electrons as well as their charge, promise to be faster and less power-consuming than traditional charge-based electronic ones. A Pure Spin current — a flow that is not accompanied by charge current — seems to be a promising way to write information for such devices. However, although ‘Spin injectors’ capable of creating such currents have been developed, their efficiency has generally remained too low for practical applications. Now, Kimura, Hamaya and colleagues have significantly improved this efficiency by using a highly ordered cobalt-iron-silicon ‘Heusler’ compound with high Spin polarization. These findings highlight the potential of Heusler compounds as Spin injectors, and move the construction of functional Spintronic devices one step forward. Heusler compound Spin injector with a high Spin polarization dramatically improves the generation efficiency of the Pure Spin current compared with a conventional ferromagnetic metal.
Sergej O. Demokritov - One of the best experts on this subject based on the ideXlab platform.
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magnetic droplet solitons generated by Pure Spin currents
Physical Review B, 2017Co-Authors: B Divinskiy, Sergei Urazhdin, V E Demidov, Alexander Kozhanov, A P Nosov, A B Rinkevich, Sergej O. DemokritovAbstract:Magnetic droplets are dynamical solitons that can be generated by locally suppressing the dynamical damping in magnetic films with perpendicular anisotropy. To date, droplets have been observed only in nanocontact Spin-torque oscillators operated by Spin-polarized electrical currents. Here, we experimentally demonstrate that magnetic droplets can be nucleated and sustained by Pure Spin currents in nanoconstriction-based Spin Hall devices. Micromagnetic simulations support our interpretation of the data, and indicate that in addition to the stationary droplets, propagating solitons can be also generated in the studied system, which can be utilized for the information transmission in Spintronic applications.
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chemical potential of quasi equilibrium magnon gas driven by Pure Spin current
Nature Communications, 2017Co-Authors: V E Demidov, Sergei Urazhdin, B Divinskiy, A B Rinkevich, V D Bessonov, V V Ustinov, Sergej O. DemokritovAbstract:Pure Spin currents provide the possibility to control the magnetization state of conducting and insulating magnetic materials. They allow one to increase or reduce the density of magnons, and achieve coherent dynamic states of magnetization reminiscent of the Bose-Einstein condensation. However, until now there was no direct evidence that the state of the magnon gas subjected to Spin current can be treated thermodynamically. Here, we show experimentally that the Spin current generated by the Spin-Hall effect drives the magnon gas into a quasi-equilibrium state that can be described by the Bose-Einstein statistics. The magnon population function is characterized either by an increased effective chemical potential or by a reduced effective temperature, depending on the Spin current polarization. In the former case, the chemical potential can closely approach, at large driving currents, the lowest-energy magnon state, indicating the possibility of Spin current-driven Bose-Einstein condensation.
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chemical potential of quasi equilibrium magnon gas driven by Pure Spin current
Nature Communications, 2017Co-Authors: V E Demidov, Sergei Urazhdin, B Divinskiy, A B Rinkevich, V D Bessonov, V V Ustinov, Sergej O. DemokritovAbstract:Pure Spin currents provide the possibility to control the magnetization state of conducting and insulating magnetic materials. They allow one to increase or reduce the density of magnons, and achieve coherent dynamic states of magnetization reminiscent of the Bose–Einstein condensation. However, until now there was no direct evidence that the state of the magnon gas subjected to Spin current can be treated thermodynamically. Here, we show experimentally that the Spin current generated by the Spin-Hall effect drives the magnon gas into a quasi-equilibrium state that can be described by the Bose–Einstein statistics. The magnon population function is characterized either by an increased effective chemical potential or by a reduced effective temperature, depending on the Spin current polarization. In the former case, the chemical potential can closely approach, at large driving currents, the lowest-energy magnon state, indicating the possibility of Spin current-driven Bose–Einstein condensation. Spin current-induced quasi-equilibrium state of magnon gas described by the Bose–Einstein statistics has been previously theoretically predicted. Here, authors experimentally show that the Spin current-driven magnon distribution can be treated thermodynamically, and potentially form a Bose–Einstein condensate.
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Magnetization oscillations and waves driven by Pure Spin currents
Physics Reports, 2017Co-Authors: Vladimir Demidov, Aomar Anane, G De Loubens, Sergei Urazhdin, O Klein, Vincent Cros, Sergej O. DemokritovAbstract:Recent advances in the studies of Pure Spin currents – flows of angular momentum (Spin) not accompanied by the electric currents – have opened new horizons for the emerging technologies based on the electron's Spin degree of freedom, such as Spintronics and magnonics. The main advantage of Pure Spin current, as compared to the Spin-polarized electric current, is the possibility to exert Spin transfer torque on the magnetization in thin magnetic films without the electrical current flow through the material. In addition to minimizing Joule heating and electromigration effects, this enables the implementation of Spin torque devices based on the low-loss insulating magnetic materials, and offers an unprecedented geometric flexibility. Here we review the recent experimental achievements in investigations of magnetization oscillations excited by Pure Spin currents in different nanomagnetic systems based on metallic and insulating magnetic materials. We discuss the spectral properties of Spin-current nano-oscillators, and relate them to the spatial characteristics of the excited dynamic magnetic modes determined by the spatially-resolved measurements. We also show that these systems support locking of the oscillations to external microwave signals, as well as their mutual synchronization, and can be used as efficient nanoscale sources of propagating Spin waves.
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route toward high speed nano magnonics provided by Pure Spin currents
Applied Physics Letters, 2016Co-Authors: B Divinskiy, Sergej O. Demokritov, V E Demidov, A B Rinkevich, Sergei UrazhdinAbstract:We study experimentally the possibility to utilize pulses of Pure Spin current, produced via the nonlocal Spin injection mechanism, to generate short packets of Spin waves propagating in nanoscale magnetic waveguides. Spatially and time-resolved micro-focus Brillouin light scattering spectroscopy measurements demonstrate that the excitation by Spin current results in extremely fast transient response, enabling efficient generation of short Spin-wave packets with duration down to a few nanoseconds. The proposed method opens a route for the implementation of high-speed magnonic systems for transmission and processing of information on the nanoscale.
Shinya Yamada - One of the best experts on this subject based on the ideXlab platform.
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Pure Spin current transport in a SiGe alloy
Applied Physics Express, 2018Co-Authors: Takahiro Naito, Shinya Yamada, Michihiro Yamada, Makoto Tsukahara, Kentarou Sawano, Kohei HamayaAbstract:Using four-terminal nonlocal magnetoresistance measurements in lateral Spin-valve devices with Si0.1Ge0.9, we study Pure Spin current transport in a degenerate SiGe alloy (n ~ 5.0 × 1018 cm−3). Clear nonlocal Spin-valve signals and Hanle effect curves, indicating generation, transport, and detection of Pure Spin currents, are observed. The Spin diffusion length and Spin lifetime of the Si0.1Ge0.9 layer at low temperatures are reliably estimated to be ~0.5 µm and ~0.2 ns, respectively. This study demonstrates the possibility of exploring physics and developing Spintronic applications using SiGe alloys.
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Pure Spin current transport in a sige alloy
arXiv: Mesoscale and Nanoscale Physics, 2018Co-Authors: Takahiro Naito, Shinya Yamada, Michihiro Yamada, Makoto Tsukahara, Kentarou Sawano, K HamayaAbstract:Using four-terminal nonlocal magnetoresistance measurements in lateral Spin-valve (LSV) devices with Si$_{\rm 0.1}$Ge$_{\rm 0.9}$, we study Pure Spin current transport in a degenerate SiGe alloy ($n \sim$ 5.0 $\times$ 10$^{18}$ cm$^{-3}$). Clear nonlocal Spin-valve signals and Hanle-effect curves, indicating generation, manipulation, and detection of Pure Spin currents, are observed. The Spin diffusion length of the Si$_{\rm 0.1}$Ge$_{\rm 0.9}$ layer at low temperatures is estimated to be $\sim$ 0.5 $\mu$m. Because of the similar conduction band structure to Pure Ge, the Spin-transport properties are nearly consistent with the recent results of degenerate Ge [Phys. Rev. B {\bf 94}, 245302 (2016); Phys. Rev. B {\bf 95}, 161304(R) (2017).]. This study shows a possibility to explore physics and to develop Spintronic applications in the field of SiGe alloys.
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direct evidence for suppression of the kondo effect due to Pure Spin current
Physical Review B, 2016Co-Authors: K Hamaya, Shinya Yamada, T Kurokawa, S Oki, Takeshi Kanashima, Tomoyasu TaniyamaAbstract:We study the effect of a Pure Spin current on the Kondo singlet in a diluted magnetic alloy using non-local lateral Spin valve structures with highly Spin polarized Co2FeSi electrodes. Temperature dependence of the non-local Spin signals shows a sharp reduction with decreasing temperature, followed by a plateau corresponding to the low temperature Fermi liquid regime below the Kondo temperature (TK). The Spin diffusion length of the Kondo alloy is found to increase with the evolution of Spin accumulation. The results are in agreement with the intuitive description that the Kondo singlet cannot survive any more in sufficiently large Spin accumulation even below TK.
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greatly enhanced generation efficiency of Pure Spin currents in ge using heusler compound co2fesi electrodes
Applied Physics Express, 2014Co-Authors: K Kasahara, Masanobu Miyao, Shinya Yamada, Kentarou Sawano, Yuichi Fujita, K HamayaAbstract:We show nonlocal Spin transport in n-Ge-based lateral Spin-valve devices with highly ordered Co2FeSi/n+-Ge Schottky tunnel contacts. Clear Spin-valve signals and Hanle effect curves are demonstrated at low temperatures, indicating the generation, manipulation, and detection of Pure Spin currents in n-Ge. The obtained Spin generation efficiency of ~0.12 is about two orders of magnitude larger than that for a previously reported device with Fe/MgO tunnel barrier contacts. Considering the Spin-related behavior with temperature evolution, we infer that it is necessary to simultaneously demonstrate a high Spin generation efficiency and improve the quality of the transport channel to realize Ge-based Spintronic devices.
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large enhancement in the generation efficiency of Pure Spin currents in ge using heusler compound co_2fesi electrodes
arXiv: Materials Science, 2013Co-Authors: K Kasahara, Masanobu Miyao, Shinya Yamada, Kentarou Sawano, Yuichi Fujita, K HamayaAbstract:We show nonlocal Spin transport in n-Ge based lateral Spin-valve devices with highly ordered Co_2FeSi/n^+-Ge Schottky tunnel contacts. Clear Spin-valve signals and Hanle-effect curves are demonstrated at low temperatures, indicating generation, manipulation, and detection of Pure Spin currents in n-Ge. The obtained Spin generation efficiency of ~ 0.12 is about two orders of magnitude larger than that for a device with Fe/MgO tunnel-barrier contacts reported previously. Taking the Spin related behavior with temperature evolution into account, we infer that it is necessary to simultaneously demonstrate the high Spin generation efficiency and improve the quality of the transport channel for achieving Ge based Spintronic devices.
Sergei Urazhdin - One of the best experts on this subject based on the ideXlab platform.
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magnetic droplet solitons generated by Pure Spin currents
Physical Review B, 2017Co-Authors: B Divinskiy, Sergei Urazhdin, V E Demidov, Alexander Kozhanov, A P Nosov, A B Rinkevich, Sergej O. DemokritovAbstract:Magnetic droplets are dynamical solitons that can be generated by locally suppressing the dynamical damping in magnetic films with perpendicular anisotropy. To date, droplets have been observed only in nanocontact Spin-torque oscillators operated by Spin-polarized electrical currents. Here, we experimentally demonstrate that magnetic droplets can be nucleated and sustained by Pure Spin currents in nanoconstriction-based Spin Hall devices. Micromagnetic simulations support our interpretation of the data, and indicate that in addition to the stationary droplets, propagating solitons can be also generated in the studied system, which can be utilized for the information transmission in Spintronic applications.
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chemical potential of quasi equilibrium magnon gas driven by Pure Spin current
Nature Communications, 2017Co-Authors: V E Demidov, Sergei Urazhdin, B Divinskiy, A B Rinkevich, V D Bessonov, V V Ustinov, Sergej O. DemokritovAbstract:Pure Spin currents provide the possibility to control the magnetization state of conducting and insulating magnetic materials. They allow one to increase or reduce the density of magnons, and achieve coherent dynamic states of magnetization reminiscent of the Bose-Einstein condensation. However, until now there was no direct evidence that the state of the magnon gas subjected to Spin current can be treated thermodynamically. Here, we show experimentally that the Spin current generated by the Spin-Hall effect drives the magnon gas into a quasi-equilibrium state that can be described by the Bose-Einstein statistics. The magnon population function is characterized either by an increased effective chemical potential or by a reduced effective temperature, depending on the Spin current polarization. In the former case, the chemical potential can closely approach, at large driving currents, the lowest-energy magnon state, indicating the possibility of Spin current-driven Bose-Einstein condensation.
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chemical potential of quasi equilibrium magnon gas driven by Pure Spin current
Nature Communications, 2017Co-Authors: V E Demidov, Sergei Urazhdin, B Divinskiy, A B Rinkevich, V D Bessonov, V V Ustinov, Sergej O. DemokritovAbstract:Pure Spin currents provide the possibility to control the magnetization state of conducting and insulating magnetic materials. They allow one to increase or reduce the density of magnons, and achieve coherent dynamic states of magnetization reminiscent of the Bose–Einstein condensation. However, until now there was no direct evidence that the state of the magnon gas subjected to Spin current can be treated thermodynamically. Here, we show experimentally that the Spin current generated by the Spin-Hall effect drives the magnon gas into a quasi-equilibrium state that can be described by the Bose–Einstein statistics. The magnon population function is characterized either by an increased effective chemical potential or by a reduced effective temperature, depending on the Spin current polarization. In the former case, the chemical potential can closely approach, at large driving currents, the lowest-energy magnon state, indicating the possibility of Spin current-driven Bose–Einstein condensation. Spin current-induced quasi-equilibrium state of magnon gas described by the Bose–Einstein statistics has been previously theoretically predicted. Here, authors experimentally show that the Spin current-driven magnon distribution can be treated thermodynamically, and potentially form a Bose–Einstein condensate.
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Magnetization oscillations and waves driven by Pure Spin currents
Physics Reports, 2017Co-Authors: Vladimir Demidov, Aomar Anane, G De Loubens, Sergei Urazhdin, O Klein, Vincent Cros, Sergej O. DemokritovAbstract:Recent advances in the studies of Pure Spin currents – flows of angular momentum (Spin) not accompanied by the electric currents – have opened new horizons for the emerging technologies based on the electron's Spin degree of freedom, such as Spintronics and magnonics. The main advantage of Pure Spin current, as compared to the Spin-polarized electric current, is the possibility to exert Spin transfer torque on the magnetization in thin magnetic films without the electrical current flow through the material. In addition to minimizing Joule heating and electromigration effects, this enables the implementation of Spin torque devices based on the low-loss insulating magnetic materials, and offers an unprecedented geometric flexibility. Here we review the recent experimental achievements in investigations of magnetization oscillations excited by Pure Spin currents in different nanomagnetic systems based on metallic and insulating magnetic materials. We discuss the spectral properties of Spin-current nano-oscillators, and relate them to the spatial characteristics of the excited dynamic magnetic modes determined by the spatially-resolved measurements. We also show that these systems support locking of the oscillations to external microwave signals, as well as their mutual synchronization, and can be used as efficient nanoscale sources of propagating Spin waves.
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route toward high speed nano magnonics provided by Pure Spin currents
Applied Physics Letters, 2016Co-Authors: B Divinskiy, Sergej O. Demokritov, V E Demidov, A B Rinkevich, Sergei UrazhdinAbstract:We study experimentally the possibility to utilize pulses of Pure Spin current, produced via the nonlocal Spin injection mechanism, to generate short packets of Spin waves propagating in nanoscale magnetic waveguides. Spatially and time-resolved micro-focus Brillouin light scattering spectroscopy measurements demonstrate that the excitation by Spin current results in extremely fast transient response, enabling efficient generation of short Spin-wave packets with duration down to a few nanoseconds. The proposed method opens a route for the implementation of high-speed magnonic systems for transmission and processing of information on the nanoscale.
Takashi Kimura - One of the best experts on this subject based on the ideXlab platform.
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Large Pure Spin current generation in metallic nanostructures
Applied Physics A, 2013Co-Authors: Saidur R. Bakaul, Takashi KimuraAbstract:Pure Spin current corresponds to the flow of Spin angular momentum without associating any net charge current, and possesses potential to be incorporated in special functional and high-performance devices based on nonlocal Spin injection. To utilize Pure Spin current in practical devices, it is imperative to increase the Spin generation efficiency. In this article we discuss two special configurations of nonlocal devices, known as multi-terminal injector and nanopillar devices, which possess immense potential to overcome the Joule heating problem, the key bottleneck to enhance the Pure Spin current generation. We also demonstrate magnetization switching of a nanosized ferromagnet due to Pure Spin current injection in a nanopillar-based nonlocal device.
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Room-temperature generation of giant Pure Spin currents using epitaxial Co_2FeSi Spin injectors
NPG Asia Materials, 2012Co-Authors: Takashi Kimura, Masanobu Miyao, Shinya Yamada, Naoki Hashimoto, Kohei HamayaAbstract:Spintronics: Current generationTakashi Kimura, Kohei Hamaya and co-workers have generated large Pure Spin currents at room temperature, with high efficiency. Spintronic devices, which use the Spin of electrons as well as their charge, promise to be faster and less power-consuming than traditional charge-based electronic ones. A Pure Spin current — a flow that is not accompanied by charge current — seems to be a promising way to write information for such devices. However, although ‘Spin injectors’ capable of creating such currents have been developed, their efficiency has generally remained too low for practical applications. Now, Kimura, Hamaya and colleagues have significantly improved this efficiency by using a highly ordered cobalt-iron-silicon ‘Heusler’ compound with high Spin polarization. These findings highlight the potential of Heusler compounds as Spin injectors, and move the construction of functional Spintronic devices one step forward.Heusler compound Spin injector with a high Spin polarization dramatically improves the generation efficiency of the Pure Spin current compared with a conventional ferromagnetic metal.AbstractThe generation, manipulation and detection of a Pure Spin current (i.e., the flow of Spin angular momentum without a charge current) are prospective approaches for realizing next-generation Spintronic devices with ultra-low electric power consumption. Conventional ferromagnetic electrodes such as Co and NiFe have been utilized as Spin injectors to generate Pure Spin currents in nonmagnetic channels. However, the generation efficiency of Pure Spin currents is extremely low at room temperature, giving rise to a serious obstacle for device applications. Here we demonstrate the generation of giant Pure Spin currents at room temperature in lateral Spin valve devices with a highly ordered Heusler-compound Co_2FeSi (CFS) Spin injector. The generation efficiency of Pure Spin currents from the CFS Spin injectors is 10 times greater than that of the NiFe injectors, indicating that Heusler compound Spin injectors with high Spin polarization enable us to materialize a high-performance lateral Spin device. The present study is a technological jump in Spintronics, and indicates the great potential of ferromagnetic Heusler compounds with half metallicity for generating Pure Spin currents.
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Room-temperature generation of giant Pure Spin currents using epitaxial Co_2FeSi Spin injectors
NPG Asia Materials, 2012Co-Authors: Takashi Kimura, Masanobu Miyao, Shinya Yamada, Naoki Hashimoto, Kohei HamayaAbstract:The generation, manipulation and detection of a Pure Spin current (i.e., the flow of Spin angular momentum without a charge current) are prospective approaches for realizing next-generation Spintronic devices with ultra-low electric power consumption. Conventional ferromagnetic electrodes such as Co and NiFe have been utilized as Spin injectors to generate Pure Spin currents in nonmagnetic channels. However, the generation efficiency of Pure Spin currents is extremely low at room temperature, giving rise to a serious obstacle for device applications. Here we demonstrate the generation of giant Pure Spin currents at room temperature in lateral Spin valve devices with a highly ordered Heusler-compound Co_2FeSi (CFS) Spin injector. The generation efficiency of Pure Spin currents from the CFS Spin injectors is 10 times greater than that of the NiFe injectors, indicating that Heusler compound Spin injectors with high Spin polarization enable us to materialize a high-performance lateral Spin device. The present study is a technological jump in Spintronics, and indicates the great potential of ferromagnetic Heusler compounds with half metallicity for generating Pure Spin currents. Takashi Kimura, Kohei Hamaya and co-workers have generated large Pure Spin currents at room temperature, with high efficiency. Spintronic devices, which use the Spin of electrons as well as their charge, promise to be faster and less power-consuming than traditional charge-based electronic ones. A Pure Spin current — a flow that is not accompanied by charge current — seems to be a promising way to write information for such devices. However, although ‘Spin injectors’ capable of creating such currents have been developed, their efficiency has generally remained too low for practical applications. Now, Kimura, Hamaya and colleagues have significantly improved this efficiency by using a highly ordered cobalt-iron-silicon ‘Heusler’ compound with high Spin polarization. These findings highlight the potential of Heusler compounds as Spin injectors, and move the construction of functional Spintronic devices one step forward. Heusler compound Spin injector with a high Spin polarization dramatically improves the generation efficiency of the Pure Spin current compared with a conventional ferromagnetic metal.
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room temperature generation of giant Pure Spin currents using epitaxial co2fesi Spin injectors
Npg Asia Materials, 2012Co-Authors: Takashi Kimura, Masanobu Miyao, Kohei Hamaya, Shinya Yamada, Naoki HashimotoAbstract:The generation, manipulation and detection of a Pure Spin current (i.e., the flow of Spin angular momentum without a charge current) are prospective approaches for realizing next-generation Spintronic devices with ultra-low electric power consumption. Conventional ferromagnetic electrodes such as Co and NiFe have been utilized as Spin injectors to generate Pure Spin currents in nonmagnetic channels. However, the generation efficiency of Pure Spin currents is extremely low at room temperature, giving rise to a serious obstacle for device applications. Here we demonstrate the generation of giant Pure Spin currents at room temperature in lateral Spin valve devices with a highly ordered Heusler-compound Co2FeSi (CFS) Spin injector. The generation efficiency of Pure Spin currents from the CFS Spin injectors is 10 times greater than that of the NiFe injectors, indicating that Heusler compound Spin injectors with high Spin polarization enable us to materialize a high-performance lateral Spin device. The present study is a technological jump in Spintronics, and indicates the great potential of ferromagnetic Heusler compounds with half metallicity for generating Pure Spin currents. Takashi Kimura, Kohei Hamaya and co-workers have generated large Pure Spin currents at room temperature, with high efficiency. Spintronic devices, which use the Spin of electrons as well as their charge, promise to be faster and less power-consuming than traditional charge-based electronic ones. A Pure Spin current — a flow that is not accompanied by charge current — seems to be a promising way to write information for such devices. However, although ‘Spin injectors’ capable of creating such currents have been developed, their efficiency has generally remained too low for practical applications. Now, Kimura, Hamaya and colleagues have significantly improved this efficiency by using a highly ordered cobalt-iron-silicon ‘Heusler’ compound with high Spin polarization. These findings highlight the potential of Heusler compounds as Spin injectors, and move the construction of functional Spintronic devices one step forward. Heusler compound Spin injector with a high Spin polarization dramatically improves the generation efficiency of the Pure Spin current compared with a conventional ferromagnetic metal.
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Pure Spin-current-induced magnetization switching
Spintronics, 2008Co-Authors: T. Yang, Takashi Kimura, J.-b. Laloë, Yoshichika OtaniAbstract:A Spin current carries Spin angular momentum in a Spintronics device. Its interaction with a magnetic nanostructure not only gives rise to Spin-dependent transport but also excites dynamics in the magnetic state. Unlike the Spin-polarized electrical current, a Pure Spin current is useful for both fundamental and applied research because neither Oersted fields nor electrical current-related spurious effects are produced. Nonlocal electrical Spin injection is a feasible way to produce the Pure Spin current. Here we demonstrate that the nonlocal Spin valve signal is increased by an order of magnitude by improving the interface quality in a new device structure using a clean, in situ fabrication process. The generated Pure Spin current enables the magnetization reversal of a nanomagnet as efficiently as electrical current-induced magnetization switching. These results will open the door towards the realization of a Pure-Spin-current-driven device.
