The Experts below are selected from a list of 277869 Experts worldwide ranked by ideXlab platform
Masashi Shiraishi - One of the best experts on this subject based on the ideXlab platform.
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Electrical detection of the spin polarization due to charge flow in the surface state of the topological insulator bi_1 5 sb_0 5 te_1 7 se_1 3
arXiv: Materials Science, 2014Co-Authors: Yuichiro Ando, Kouki Ichiba, Kouji Segawa, Takahiro Hamasaki, Mario Novak, Yoichi Ando, Satoshi Sasaki, Fan Yang, Takayuki Kurokawa, Masashi ShiraishiAbstract:We detected the spin polarization due to charge flow in the spin non-degenerate surface state of a three dimensional topological insulator by means of an all-Electrical Method. The charge current in the bulk-insulating topological insulator Bi1.5Sb0.5Te1.7Se1.3 (BSTS) was injected/extracted through a ferromagnetic electrode made of Ni80Fe20, and an unusual current-direction-dependent magnetoresistance gives evidence for the appearance of spin polarization which leads to a spin-dependent resistance at the BSTS/Ni80Fe20 interface. In contrast, our control experiment on Bi2Se3 gave null result. These observations demonstrate the importance of the Fermi-level control for the Electrical detection of the spin polarization in topological insulators.
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Electrical detection of the spin polarization due to charge flow in the surface state of the topological insulator Bi1.5Sb0.5Te1.7Se1.3
Nano Letters, 2014Co-Authors: Yuichiro Ando, Kouki Ichiba, Kouji Segawa, Takahiro Hamasaki, Mario Novak, Yoichi Ando, Satoshi Sasaki, Fan Yang, Masashi ShiraishiAbstract:We detected the spin polarization due to charge flow in the spin non-degenerate surface state of a three dimensional topological insulator by means of an all-Electrical Method. The charge current in the bulk-insulating topological insulator Bi1.5Sb0.5Te1.7Se1.3 (BSTS) was injected/extracted through a ferromagnetic electrode made of Ni80Fe20, and an unusual current-direction-dependent magnetoresistance gives evidence for the appearance of spin polarization which leads to a spin-dependent resistance at the BSTS/Ni80Fe20 interface. In contrast, our control experiment on Bi2Se3 gave null result. These observations demonstrate the importance of the Fermi-level control for the Electrical detection of the spin polarization in topological insulators.
Timothy A. Coombs - One of the best experts on this subject based on the ideXlab platform.
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An improved FEM model for computing transport AC loss in coils made of RABiTS YBCO coated conductors for electric machines
Superconductor Science and Technology, 2011Co-Authors: Mark D Ainslie, Victor M. Rodriguez-zermeno, Weijia Yuan, Timothy J. Flack, Zhiyong Hong, Timothy A. CoombsAbstract:AC loss can be a significant problem for any applications that utilize or produce an AC current or magnetic field, such as an electric machine. The authors investigate the electromagnetic properties of high temperature superconductors with a particular focus on the AC loss in superconducting coils made from YBCO coated conductors for use in an all-superconducting electric machine. This paper presents an improved 2D finite element model for the cross-section of such coils, based on the H formulation. The model is used to calculate the transport AC loss of a racetrack-shaped coil using constant and magnetic field-dependent critical current densities, and the inclusion and exclusion of a magnetic substrate, as found in RABiTS (rolling-assisted biaxially textured substrate) YBCO coated conductors. The coil model is based on the superconducting stator coils used in the University of Cambridge EPEC Superconductivity Group's all-superconducting permanent magnet synchronous motor design. To validate the modeling results, the transport AC loss of a stator coil is measured using an Electrical Method based on inductive compensation by means of a variable mutual inductance. Finally, the implications of the findings on the performance of the motor are discussed.
Chunsheng Guo - One of the best experts on this subject based on the ideXlab platform.
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junction temperature measurement Method for sic bipolar junction transistor using base collector voltage drop at low current
IEEE Transactions on Power Electronics, 2019Co-Authors: Bangbing Shi, Shiwei Feng, Yamin Zhang, Kun Bai, Yuxuan Xiao, Lei Shi, Hui Zhu, Chunsheng GuoAbstract:This paper proposes an Electrical Method for estimation of the vertical junction temperature of silicon carbide bipolar junction transistors (SiC BJTs). This measurement Method is based on measurement of the base–collector voltage ( V BC) drop at a low current ( V BC(low)) during the turn- off process. This voltage shows both good sensitivity and linearity with respect to temperature. The traditional temperature-sensitive Electrical parameter V BE(low) (i.e., the base-emitter voltage at a low current) and an infrared camera are used to compare the characteristics of V BC(low). The results show that use of V BC(low) provides more accurate junction temperature and thermal resistance measurement results, which can then be used to extract the vertical junction temperature of the SiC BJT under test.
Yuichiro Ando - One of the best experts on this subject based on the ideXlab platform.
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Electrical detection of the spin polarization due to charge flow in the surface state of the topological insulator bi_1 5 sb_0 5 te_1 7 se_1 3
arXiv: Materials Science, 2014Co-Authors: Yuichiro Ando, Kouki Ichiba, Kouji Segawa, Takahiro Hamasaki, Mario Novak, Yoichi Ando, Satoshi Sasaki, Fan Yang, Takayuki Kurokawa, Masashi ShiraishiAbstract:We detected the spin polarization due to charge flow in the spin non-degenerate surface state of a three dimensional topological insulator by means of an all-Electrical Method. The charge current in the bulk-insulating topological insulator Bi1.5Sb0.5Te1.7Se1.3 (BSTS) was injected/extracted through a ferromagnetic electrode made of Ni80Fe20, and an unusual current-direction-dependent magnetoresistance gives evidence for the appearance of spin polarization which leads to a spin-dependent resistance at the BSTS/Ni80Fe20 interface. In contrast, our control experiment on Bi2Se3 gave null result. These observations demonstrate the importance of the Fermi-level control for the Electrical detection of the spin polarization in topological insulators.
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Electrical detection of the spin polarization due to charge flow in the surface state of the topological insulator Bi1.5Sb0.5Te1.7Se1.3
Nano Letters, 2014Co-Authors: Yuichiro Ando, Kouki Ichiba, Kouji Segawa, Takahiro Hamasaki, Mario Novak, Yoichi Ando, Satoshi Sasaki, Fan Yang, Masashi ShiraishiAbstract:We detected the spin polarization due to charge flow in the spin non-degenerate surface state of a three dimensional topological insulator by means of an all-Electrical Method. The charge current in the bulk-insulating topological insulator Bi1.5Sb0.5Te1.7Se1.3 (BSTS) was injected/extracted through a ferromagnetic electrode made of Ni80Fe20, and an unusual current-direction-dependent magnetoresistance gives evidence for the appearance of spin polarization which leads to a spin-dependent resistance at the BSTS/Ni80Fe20 interface. In contrast, our control experiment on Bi2Se3 gave null result. These observations demonstrate the importance of the Fermi-level control for the Electrical detection of the spin polarization in topological insulators.
T A Coombs - One of the best experts on this subject based on the ideXlab platform.
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power dissipation in hts coated conductor coils under the simultaneous action of ac and dc currents and fields
Superconductor Science and Technology, 2018Co-Authors: Boyang Shen, Jianzhao Geng, Xiuchang Zhang, James Gawith, Yingzhen Liu, Francesco Grilli, T A CoombsAbstract:This paper presents a comprehensive alternating current (AC) loss study of a circular high temperature superconductor (HTS) coated conductor coil. The AC losses from a circular double pancake coil were measured using the Electrical Method. A 2D axisymmetric H -formulation model using the FEM package in COMSOL Multiphysics has been established to match the circular geometry of the coil used in the experiment. Three scenarios have been analysed: Scenario 1 with AC transport current and DC magnetic field (experiment and simulation); Scenario 2 with DC transport current and AC magnetic field (simulation); and Scenario 3 with AC transport current and AC magnetic field (simulation and experimental data support). The angular dependence analysis on the coil under a magnetic field with different orientation angle θ has been carried out for all three scenarios. For Scenario 3, the effect of the relative phase difference Δ between the AC current and the AC field on the total AC loss of the coil has been investigated. In summary, a current/field/angle/phase dependent AC loss ( I , B , θ, Δ) study of a circular HTS coil has been carried out. The obtained results provide useful indications for the future design and research of HTS AC systems.