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Title: Effect of post annealing on spin accumulation and transport signals in Co{sub 2}FeSi/MgO/n{sup +}-Si on insulator devices

Abstract

The post annealing temperature dependence of spin accumulation and transport signals in Co{sub 2}FeSi/MgO/n{sup +}-Si on insulator were investigated. The spin signals were detected using 3- and 4-terminal Hanle, 2-terminal local and 4-terminal nonlocal magnetoresistance measurements. The post annealing temperature (T{sub A}) dependence of the magnitude in 3-terminal narrow Hanle signals is nearly constant up to T{sub A} < 400°C, however a slight decrease above T{sub A} ≥ 400°C is observed. This behavior is consistent with the T{sub A} dependence of the magnitude of 4-terminal nonlocal magnetoresistance (MR) signals. The spin polarization estimated from the 3-terminal narrow Hanle signals and the magnitude of 2-terminal local MR signals show a slight improvement with increasing post annealing temperature with a peak at around 325°C and then start reducing slowly. The slight increase in the spin signal would be due to high spin polarization of Co{sub 2}FeSi as a result of structural ordering. The 2-terminal local MR signals do not vary significantly by annealing between as-deposited and T{sub A} = 400°C, indicating the robustness of our device. This result would be useful for future Si spintronics devices.

Authors:
; ; ; ;  [1];  [2]
  1. Corporate Research & Development Center, Toshiba Corporation, 1 Komukai-Toshiba, Kawasaki, Kanagawa 212-8582 (Japan)
  2. Department of Materials Science, Tohoku University, 6-6-02 Aramaki-Aza-Aoba, 980-8579 Sendai (Japan)
Publication Date:
OSTI Identifier:
22611426
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Advances; Journal Volume: 6; Journal Issue: 7; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ANNEALING; COBALT COMPOUNDS; EQUIPMENT; IRON COMPOUNDS; MAGNESIUM OXIDES; MAGNETORESISTANCE; N-TYPE CONDUCTORS; SIGNALS; SILICON; SILICON COMPOUNDS; SPIN; SPIN ORIENTATION; TEMPERATURE DEPENDENCE; TERNARY ALLOY SYSTEMS

Citation Formats

Tiwari, Ajay, E-mail: ajay1.tiwari@toshiba.co.jp, Inokuchi, Tomoaki, Ishikawa, Mizue, Sugiyama, Hideyuki, Saito, Yoshiaki, and Tezuka, Nobuki. Effect of post annealing on spin accumulation and transport signals in Co{sub 2}FeSi/MgO/n{sup +}-Si on insulator devices. United States: N. p., 2016. Web. doi:10.1063/1.4960210.
Tiwari, Ajay, E-mail: ajay1.tiwari@toshiba.co.jp, Inokuchi, Tomoaki, Ishikawa, Mizue, Sugiyama, Hideyuki, Saito, Yoshiaki, & Tezuka, Nobuki. Effect of post annealing on spin accumulation and transport signals in Co{sub 2}FeSi/MgO/n{sup +}-Si on insulator devices. United States. doi:10.1063/1.4960210.
Tiwari, Ajay, E-mail: ajay1.tiwari@toshiba.co.jp, Inokuchi, Tomoaki, Ishikawa, Mizue, Sugiyama, Hideyuki, Saito, Yoshiaki, and Tezuka, Nobuki. 2016. "Effect of post annealing on spin accumulation and transport signals in Co{sub 2}FeSi/MgO/n{sup +}-Si on insulator devices". United States. doi:10.1063/1.4960210.
@article{osti_22611426,
title = {Effect of post annealing on spin accumulation and transport signals in Co{sub 2}FeSi/MgO/n{sup +}-Si on insulator devices},
author = {Tiwari, Ajay, E-mail: ajay1.tiwari@toshiba.co.jp and Inokuchi, Tomoaki and Ishikawa, Mizue and Sugiyama, Hideyuki and Saito, Yoshiaki and Tezuka, Nobuki},
abstractNote = {The post annealing temperature dependence of spin accumulation and transport signals in Co{sub 2}FeSi/MgO/n{sup +}-Si on insulator were investigated. The spin signals were detected using 3- and 4-terminal Hanle, 2-terminal local and 4-terminal nonlocal magnetoresistance measurements. The post annealing temperature (T{sub A}) dependence of the magnitude in 3-terminal narrow Hanle signals is nearly constant up to T{sub A} < 400°C, however a slight decrease above T{sub A} ≥ 400°C is observed. This behavior is consistent with the T{sub A} dependence of the magnitude of 4-terminal nonlocal magnetoresistance (MR) signals. The spin polarization estimated from the 3-terminal narrow Hanle signals and the magnitude of 2-terminal local MR signals show a slight improvement with increasing post annealing temperature with a peak at around 325°C and then start reducing slowly. The slight increase in the spin signal would be due to high spin polarization of Co{sub 2}FeSi as a result of structural ordering. The 2-terminal local MR signals do not vary significantly by annealing between as-deposited and T{sub A} = 400°C, indicating the robustness of our device. This result would be useful for future Si spintronics devices.},
doi = {10.1063/1.4960210},
journal = {AIP Advances},
number = 7,
volume = 6,
place = {United States},
year = 2016,
month = 7
}
  • We study in detail how the bias voltage (V{sub bias}) and interface resistance (RA) depend on the magnitude of spin accumulation signals (|ΔV| or |ΔV|/I, where I is current) as detected by three-terminal Hanle measurements in CoFe/MgO/Si on insulator (SOI) devices with various MgO layer thicknesses and SOI carrier densities. We find the apparent maximum magnitude of spin polarization as a function of V{sub bias} and the correlation between the magnitude of spin accumulation signals and the shape of differential conductance (dI/dV) curves within the framework of the standard spin diffusion model. All of the experimental results can be explainedmore » by taking into account the density of states (DOS) in CoFe under the influence of the applied V{sub bias} and the quality of MgO tunnel barrier. These results indicate that it is important to consider the DOS of the ferromagnetic materials under the influence of an applied V{sub bias} and the quality of tunnel barrier when observing large spin accumulation signals in Si.« less
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  • In this study, we investigate the spin transport in normal metal (NM)/insulator (I)/topological insulator (TI) coupled to ferromagnetic insulator (FI) structures. In particular, we focus on the barrier thickness dependence of the spin transport inside the bulk gap of the TI with FI. The TI with FI is described by two-dimensional (2D) Dirac Hamiltonian. The energy profile of the insulator is assumed to be a square with barrier height V and thickness d along the transport-direction. This structure behaves as a tunnel device for 2D Dirac electrons. The calculation is performed for the spin conductance with changing the barrier thicknessmore » and the components of magnetization of FI layer. It is found that the spin conductance decreases with increasing the barrier thickness. Also, the spin conductance is strongly dependent on the polar angle θ, which is defined as the angle between the axis normal to the FI and the magnetization of FI layer. These results indicate that the structures are promising candidates for novel tunneling magnetoresistance devices.« less