Over 1% magnetoresistance ratio at room temperature in non-degenerate silicon-based lateral spin valves

Koike, Hayato; Lee, S.; Ohshima, Ryo; Shigematsu, Ei; Goto, Minori; Miwa, Shinji; Suzuki, Y.; Sasaki, T.; Ando, Yoshinori; Shiraishi, Masashi

doi:10.35848/1882-0786/aba22c

Cited by 10 publications

(4 citation statements)

References 30 publications

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“…The Au–Si and/or Au-Al-Si liquid phases diffuse mainly along the AlN/Si interface (Fig. 3 i) due to the strong tensile strain 29 , and the interface is more susceptible to destruction than the other areas. Finally, Au reaches the FM electrodes and invades the MgO tunnelling barrier.…”

Section: Resultsmentioning

confidence: 99%

Investigation of the thermal tolerance of silicon-based lateral spin valves

Yamashita

Lee

Ohshima

et al. 2021

Sci Rep

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Improvement in the thermal tolerance of Si-based spin devices is realized by employing thermally stable nonmagnetic (NM) electrodes. For Au/Ta/Al electrodes, intermixing between Al atoms and Au atoms occurs at approximately 300 °C, resulting in the formation of a Au/Si interface. The Au–Si liquid phase is formed and diffuses mainly along an in-plane direction between the Si and AlN capping layers, eventually breaking the MgO layer of the ferromagnetic (FM) metal/MgO electrodes, which is located 7 µm away from the NM electrodes. By changing the layer structure of the NM electrode from Au/Ta/Al to Au/Ta, the thermal tolerance is clearly enhanced. Clear spin transport signals are obtained even after annealing at 400 °C. To investigate the effects of Mg insertion in FM electrodes on thermal tolerance, we also compare the thermal tolerance among Fe/Co/MgO, Fe/Co/Mg/MgO and Fe/Co/MgO/Mg contacts. Although a highly efficient spin injection has been reported by insertion of a thin Mg layer below or above the MgO layer, these thermal tolerances decrease obviously.

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Section: Resultsmentioning

confidence: 99%

Investigation of the thermal tolerance of silicon-based lateral spin valves

Yamashita

Lee

Ohshima

et al. 2021

Sci Rep

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show abstract

“…The Au-Si and/or Au-Al-Si liquid phases diffuse mainly along the AlN/Si interface (Fig. 3h) due to the strong tensile strain 27 , and the interface is more susceptible to destruction than the other areas. Finally, Au reaches the FM electrodes and invades the MgO tunnelling barrier.…”

Section: Figures 2a and 2b Show Optical Microscopy Images Of Sample Amentioning

confidence: 99%

Improved Thermal Tolerance of Silicon-based Lateral Spin Valves

Yamashita¹,

Lee²,

Ohshima³

et al. 2020

Preprint

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Improvement in the thermal tolerance of Si-based spin devices is realized by employing thermally stable nonmagnetic (NM) electrodes. For Au/Ta/Al electrodes, intermixing between Al atoms and Au atoms occurs at approximately 300°C, resulting in the formation of a Au/Si interface. The Au-Si liquid phase is formed and diffuses mainly along an in-plane direction between the Si and AlN capping layers, eventually breaking the MgO layer of the ferromagnetic (FM) metal/MgO electrodes, which is located 7 mm away from the NM electrodes. By changing the layer structure of the NM electrode from Au/Ta/Al to Au/Ta, the thermal tolerance is clearly enhanced. Clear spin transport signals are obtained even after annealing at 400°C. To investigate the effects of Mg insertion in FM electrodes on thermal tolerance, we also compare the thermal tolerance among Fe/Co/MgO, Fe/Co/Mg/MgO and Fe/Co/MgO/Mg contacts. Although a highly efficient spin injection has been reported by insertion of a thin Mg layer below or above the MgO layer, these thermal tolerances decrease obviously.

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“…Many studies have been conducted to realize spin transistors; however, the performance of the present devices is far from the level for realistic applications. A magnetoresistance (MR) ratio of more than 100% is required, but the highest MR ratio reported thus far is ≈1% (1.4% at room temperature [ 14 ] and 0.12% at 8 K [ 15 ] ) for Si‐based devices and ≈10% for III–V semiconductor‐based devices when measured under a constant‐voltage condition at ≈1.4 K (or 80% under a constant‐current condition with Esaki‐diode tunneling contacts). [ 9 ] In theory, to obtain a large MR ratio, the contact resistance of FM electrode/nonmagnetic semiconductor interfaces needs to be adjusted within a narrow window.…”

Section: Introductionmentioning

confidence: 99%

Giant Spin‐Valve Effect in Planar Spin Devices Using an Artificially Implemented Nanolength Mott‐Insulator Region

et al. 2023

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Developing technology to realize oxide-based nanoscale planar integrated circuits is in high demand for next-generation multifunctional electronics. Oxide circuits can have a variety of unique functions, including ferromagnetism, ferroelectricity, multiferroicity, superconductivity, and mechanical flexibility. In particular, for spin-transistor applications, the wide tunability of the physical properties due to the presence of multiple oxide phases is valuable for precise conductivity matching between the channel and ferromagnetic electrodes. This feature is essential for realistic spin-transistor operations. Here, a substantially large magnetoresistance (MR) ratio of up to ≈140% is demonstrated for planar-type (La,Sr)MnO 3 (LSMO)-based spin-valve devices. This MR ratio is 10-100 times larger than the best values obtained for semiconductor-based planar devices, which have been studied over the past three decades. This structure is prepared by implementing an artificial nanolength Mott-insulator barrier region using the phase transition of metallic LSMO. The barrier height of the Mott-insulator region is only 55 meV, which enables the large MR ratio. Furthermore, a successful current modulation, which is a fundamental functionality for spin transistors, is shown. These results open up a new avenue for realizing oxide planar circuits with unique functionalities that conventional semiconductors cannot achieve.

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Over 1% magnetoresistance ratio at room temperature in non-degenerate silicon-based lateral spin valves

Cited by 10 publications

References 30 publications

Investigation of the thermal tolerance of silicon-based lateral spin valves

Investigation of the thermal tolerance of silicon-based lateral spin valves

Improved Thermal Tolerance of Silicon-based Lateral Spin Valves

Giant Spin‐Valve Effect in Planar Spin Devices Using an Artificially Implemented Nanolength Mott‐Insulator Region

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