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176 results on '"Yu, G. Q."'

1. Stochastic p-Bits Based on Spin-Orbit Torque Magnetic Tunnel Junctions

Author

Li, X. H., Zhao, M. K., Zhang, R., Wan, C. H., Wang, Y. Z., Luo, X. M., Liu, S. Q., Xia, J. H., Yu, G. Q., and Han, X. F.

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics, Condensed Matter - Materials Science, Physics - Applied Physics
Abstract

Stochastic p-Bit devices play a pivotal role in solving NP-hard problems, neural network computing, and hardware accelerators for algorithms such as the simulated annealing. In this work, we focus on Stochastic p-Bits based on high-barrier magnetic tunnel junctions (HB-MTJs) with identical stack structure and cell geometry, but employing different spin-orbit torque (SOT) switching schemes. We conducted a comparative study of their switching probability as a function of pulse amplitude and width of the applied voltage. Through experimental and theoretical investigations, we have observed that the Y-type SOT-MTJs exhibit the gentlest dependence of the switching probability on the external voltage. This characteristic indicates superior tunability in randomness and enhanced robustness against external disturbances when Y-type SOT-MTJs are employed as stochastic p-Bits. Furthermore, the random numbers generated by these Y-type SOT-MTJs, following XOR pretreatment, have successfully passed the National Institute of Standards and Technology (NIST) SP800-22 test. This comprehensive study demonstrates the high performance and immense potential of Y-type SOT-MTJs for the implementation of stochastic p-Bits.

Published
2023

2. Continuous nucleation switching driven by spin-orbit torques

Author

Wan, C. H., Stebliy, M. E., Wang, X., Yu, G. Q., Han, X. F., Kolesnikov, A. G., Bazrov, M. A., Letushev, M. E., Ognev, A. V., and Samardak, A. S.

Subjects
Physics - Applied Physics
Abstract

Continuous switching driven by spin-orbit torque (SOT) is preferred to realize neuromorphic computing in a spintronic manner. Here we have applied focused ion beam (FIB) to selectively illuminate patterned regions in a Pt/Co/MgO strip with perpendicular magnetic anisotropy (PMA), soften the illuminated areas and realize the continuous switching by a SOT-driven nucleation process. It is found that a large in-plane field is a benefit to reduce the nucleation barrier, increase the number of nucleated domains and intermediate states during the switching progress, and finally flatten the switching curve. We proposed a phenomenological model for descripting the current dependence of magnetization and the dependence of the number of nucleation domains on the applied current and magnetic field. This study can thus promote the birth of SOT devices, which are promising in neuromorphic computing architectures., Comment: 12 pages with 3 figures

Published
2020

3. Magnon Valves Based on YIG/NiO/YIG All-Insulating Magnon Junctions

Author

Guo, C. Y., Wan, C. H., Wang, X., Fang, C., Tang, P., Kong, W. J., Zhao, M. K., Jiang, L. N., Tao, B. S., Yu, G. Q., and Han, X. F.

Subjects
Physics - Applied Physics
Abstract

As an alternative angular momentum carrier, magnons or spin waves can be utilized to encode information and breed magnon-based circuits with ultralow power consumption and non-Boolean data processing capability. In order to construct such a circuit, it is indispensable to design some electronic components with both long magnon decay and coherence length and effective control over magnon transport. Here we show that an all-insulating magnon junctions composed by a magnetic insulator (MI1)/antiferromagnetic insulator (AFI)/magnetic insulator (MI2) sandwich (Y3Fe5O12/NiO/Y3Fe5O12) can completely turn a thermogradient-induced magnon current on or off as the two Y3Fe5O12 layers are aligned parallel or anti-parallel. The magnon decay length in NiO is about 3.5~4.5 nm between 100 K and 200 K for thermally activated magnons. The insulating magnon valve (magnon junction), as a basic building block, possibly shed light on the naissance of efficient magnon-based circuits, including non-Boolean logic, memory, diode, transistors, magnon waveguide and switches with sizable on-off ratios., Comment: 9 pages, 7 figures

Published
2018
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4. Magnon Valve Effect Between Two Magnetic Insulators

Author

Wu, H., Huang, L., Fang, C., Yang, B. S., Wan, C. H., Yu, G. Q., Feng, J. F., Wei, H. X., and Han, X. F.

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

The key physics of the spin valve involves spin-polarized conduction electrons propagating between two magnetic layers such that the device conductance is controlled by the relative magnetization orientation of two magnetic layers. Here, we report the effect of a magnon valve which is made of two ferromagnetic insulators (YIG) separated by a nonmagnetic spacer layer (Au). When a thermal gradient is applied perpendicular to the layers, the inverse spin Hall voltage output detected by a Pt bar placed on top of the magnon valve depends on the relative orientation of the magnetization of two YIG layers, indicating the magnon current induced by spin Seebeck effect at one layer affects the magnon current in the other layer separated by Au. We interpret the magnon valve effect by the angular momentum conversion and propagation between magnons in two YIG layers and conduction electrons in the Au layer. The temperature dependence of magnon valve ratio shows approximately a power law, supporting the above magnon-electron spin conversion mechanism. This work opens a new class of valve structures beyond the conventional spin valves., Comment: 13 pages, 4 figures

Published
2018
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5. Self-stabilized true random number generator based on spin–orbit torque magnetic tunnel junctions without calibration.

Author

Xu, Y. Q., Li, X. H., Zhang, R., Wan, C. H., Wang, Y. Z., Liu, S. Q., Luo, X. M., Lan, G. B., Xia, J. H., Yu, G. Q., and Han, X. F.

Subjects
RANDOM number generators, MAGNETIC tunnelling, MAGNETIC torque, RANDOM numbers, PROBABILITY theory
Abstract

Magnetic tunnel junction (MTJ)-based true random number generators (TRNG), which are promisingly utilized as hardware accelerators for probabilistic computing, may suffer intrinsic performance drifting and fluctuation in the probability space and performance variations in device arrays. In order to preventively avoid these concerns, it is necessary to develop strategies that can help MTJ-based TRNG to be self-stabilized and calibration-free. Here, we derived a simple and easily handleable strategy that only depends on the current sampled state of an MTJ device without any historical or statistic information or a pre-calibrated probabilistic switching property to dynamically tune its sampling probability for the next sampling operation. In this way, the long-term sampling probability of the MTJ can be proved to automatically converge into a desired probability with little fluctuation and drifting. We further experimentally demonstrate such a self-stabilized MTJ-based TRNG. Our results show that the TRNG can generate binary random numbers with any destined probability regardless of its initial state. Furthermore, the TRNG also displays the desired capability of excellently hedging against performance drifting and fluctuations. All these combined allow the self-stabilized TRNG without calibration to be more viable for high-quality entropy source applications. [ABSTRACT FROM AUTHOR]

Published
2024
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15. HLA-B13:01 and the Dapsone Hypersensitivity Syndrome

Author

Zhang, F.-R., Liu, H., Irwanto, A., Fu, X.-A., Li, Y., Yu, G.-Q., Yu, Y.-X., Chen, M.-F., Low, H.-Q., Li, J.-H., Bao, F.-F., Foo, J.-N., Bei, J.-X., Jia, X.-M., Liu, J., Liany, H., Wang, N., Niu, G.-Y., Wang, Z.-Z., Shi, B.-Q., Tian, H.-Q., Liu, H.-X., Ma, S.-S., Zhou, Y., You, J.-B., Yang, Q., Wang, C., Chu, T.-S., Liu, D.-C., Yu, X.-L., Sun, Y.-H., Ning, Y., Wei, Z.-H., Chen, S.-L., Chen, X.-C., Zhang, Z.-X., Liu, Y.-X., Pulit, S. L., Wu, W.-B., Zheng, Z.-Y., Yang, R.-D., Long, H., Liu, Z.-S., Wang, J.-Q., Li, M., Zhang, L.-H., Wang, H., Wang, L.-M., Xiao, P., Li, J.-L., Huang, Z.-M., Huang, J.-X., Li, Z., Xiong, L., Yang, J., Wang, X.-D., Yu, D.-B., Lu, X.-M., Zhou, G.-Z., Yan, L.-B., Shen, J.-P., Zhang, G.-C., Zeng, Y.-X., de Bakker, P. I., Chen, S.-M., and Liu, J.-J.

Published
2013
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25. Conductance enhancement due to interface magnons in electron-beam evaporated MgO magnetic tunnel junctions with CoFeB free layer deposited at different pressure.

Author

Guo., P., Li, D. L., Feng, J. F., Kurt, H., Yu, G. Q., Chen, J. Y., Wei, H. X., Coey, J. M. D., and Han, X. F.

Subjects
ELECTRIC admittance, MAGNONS, ELECTRON beam research, MAGNESIUM oxide, MAGNETIC tunnelling
Abstract

Electron-beam evaporated MgO-based magnetic tunnel junctions have been fabricated with the CoFeB free layer deposited at Ar pressure from 1 to 4mTorr, and their tunneling process has been studied as a function of temperature and bias voltage. By changing the growth pressure, the junction dynamic conductance d²I/dV², inelastic electron tunneling spectrum d I/dV, and tunneling magnetoresistance vary with temperature. Moreover, the low-energy magnon cutoff energy EC derived from the conductance versus temperature curve agrees with interface magnon energy obtained directly from the inelastic electron tunneling spectrum, which demonstrates that interface magnons are involved in the electron tunneling process, opening an additional conductance channel and thus enhancing the total conductance. [ABSTRACT FROM AUTHOR]

Published
2014
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26. Tunneling processes in asymmetric double barrier magnetic tunnel junctions with a thin top MgO layer.

Author

Li, D. L., Feng, J. F., Yu, G. Q., Guo, P., Chen, J. Y., Wei, H. X., Han, X. F., and Coey, J. M. D.

Subjects
ELECTRON tunneling, MAGNETIC tunnelling, MAGNESIUM oxide, MAGNONS, PHONONS
Abstract

Dynamic conductance dI/dV and inelastic electron tunneling spectroscopy (IETS) d2I/dV2 have been measured at different temperatures for double barrier magnetic tunnel junctions with a thin top MgO layer. The resistance in the antiparallel state exhibits a normal tunnel-like behavior, while the resistance in the parallel state shows metallic-like transport, indicating the presence of pinholes in the thin top MgO layer. Three IETS peaks are the zero-bias anomaly, interface magnons, and barrier phonons in both the parallel and antiparallel states. The zero-bias anomaly is the strongest peak in the parallel state and its intensity decreases with temperature. The magnon has the largest intensity in the antiparallel state and its intensity also decreases with temperature. The origins of the dips and peaks in the dI/dV-V curve are also discussed. [ABSTRACT FROM AUTHOR]

Published
2013
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29. Electric-field control of CoFeB/IrMn exchange bias system.

Author

Rizwan, Syed, Yu, G. Q., Zhang, S., Zhao, Y. G., and Han, X. F.

Subjects
*ELECTRIC fields, *SPINTRONICS, *NANOTECHNOLOGY, *MAGNETISM, *CHARGE exchange, *MULTIFERROIC materials
Abstract

The electrically controlled spintronic devices based on magnetism at the interface is a key challenge today. We have studied the top sub./CoFeB/IrMn and bottom sub./IrMn/CoFeB pinned exchange bias systems as a function of electric field at room temperature deposited on the (011)-Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT) piezoelectric substrate. It was found that the electric-field tuning of exchange bias was very small although both the structures show good regular magnetoelectric coupling. We propose an alternative way to control the exchange bias via electric field in the multilayered structure by inserting a metallic spacer layer between exchange bias bilayer and bottom free magnetic layer, i.e., PMN-PT/CoFeB/Cu/CoFeB/IrMn. We successfully tuned the exchange bias of such multilayer structure as function of electric field at room temperature. Our results show a step forward in utilizing electrically controlled multiferroic systems for practical applications. [ABSTRACT FROM AUTHOR]

Published
2012
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30. Giant magnetoresistance and unusual hysteresis behavior in La0.67Ca0.33MnO3/xCuO (x=20%) composite.

Author

Miao, J. H., Yuan, S. L., Xiao, X., Ren, G. M., Yu, G. Q., Wang, Y. Q., and Yin, S. Y.

Subjects
MAGNETORESISTANCE, ELECTRIC resistance, MAGNETICS, MAGNETIC fields, METALS, HYSTERESIS
Abstract

La0.67Ca0.33MnO3(LCMO)/xCuO (x=0 and 20 mole %) composites were fabricated and investigated in detail for their electrical and magnetic transport properties. Compared with pure LCMO, the magnetoresistance (MR) effect for x=20% sample is substantially enhanced especially at the vicinity of TIM, where TIM is the transition temperature from insulator to metallic state. Application of even a low magnetic field of H=0.5 T leads to a MR value as large as ∼98%. It is interesting to note that at the same temperature region where substantial MR effect is obtained, considerable thermal and magnetic hystereses in resistivity (ρ) appear. The measurement of magnetization (M) versus magnetic field (H) also exhibits an unusual magnetic hysteresis. Due to the absence of these unusual hysteresis behaviors in pure LCMO, it is discussed that the abnormal experimental observations are attributed to the spin disorder especially at grain boundaries induced by the interaction product layer between LCMO and CuO. [ABSTRACT FROM AUTHOR]

Published
2007
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31. Distinguishing the effect of surface passivation from the effect of size on the photonic and electronic behavior of porous silicon.

Author

Pan, L. K., Sun, Chang Q., Yu, G. Q., Zhang, Q. Y., Fu, Y. Q., and Tay, B. K.

Subjects
PHOTONICS, ELECTRONICS, POROUS silicon, SEMICONDUCTORS, PHOTOEMISSION
Abstract

CF4 plasma-passivation enhanced size dependence of the blueshift in photoemission and photoabsorption, E2p-level shift, and band-gap expansion of porous silicon has been measured and analyzed numerically based on the recent “bond order-length-strength” correlation [ C. Q. Sun, Phys. Rev. B 69, 045105 (2004) ]. Matching predictions to the measurements conducted before and after fluorination reveals that fluorination further enhances both the crystal binding intensity that determines the band gap and core level shift and the electron-phonon coupling that contributes to the energies of photoemission and photoabsorption. This approach enables us to discriminate the effect of surface-bond contraction from the effect of surface-bond nature alteration on the unusual behavior of photons, phonons, and electrons in nanosolid Si. [ABSTRACT FROM AUTHOR]

Published
2004
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32. Impact of serum FGF23 levels on blood pressure of patients with chronic kidney disease.

Author

LI, J. -X., YU, G. -Q., and ZHUANG, Y. -Z.

Abstract

OBJECTIVE: To investigate the impact of serum FGF23 levels on blood pressure of patients with chronic kidney disease (CKD). PATIENTS AND METHODS: 128 patients with chronic kidney disease were selected from February 2013 to January 2016. Using CKD staging method, all the patients were divided into 1 to 5 stages according to the glomerular filtration rate. Enzyme-Linked ImmunoSorbent Assay (ELISA) was used to detect serum FGF23 levels of CKD patients and healthy control subjects. 24 h blood pressure monitoring method was used to monitor the mean arterial pressure of patients. Spearman- related analysis method was used to statistically analyze serum FGF23 level, mean arterial pressure and glomerular filtration rate. RESULTS: The serum FGF23 levels of CKD patients were significantly higher than those of the healthy control subjects (p<0.05). Also, FGF23 expression levels in serum were positively correlated with mean arterial pressure based on the results of the Spearman-related analysis. On the other hand, FGF23 expression levels in serum were negatively correlated with glomerular filtration rate. The FGF23 expression levels in serum of the patients were significantly decreased along with the decrease of mean arterial pressure. CONCLUSIONS: Serum FGF23 level is positively correlated with mean arterial pressure and negatively correlated with glomerular filtration rate. So, FGF23 has an important clinical significance that can reflect blood pressure and treatment effect of dialysis of CKD patients. [ABSTRACT FROM AUTHOR]

Published
2018

35. HLA-B*13:01and the Dapsone Hypersensitivity Syndrome

Author

Zhang, F.-R., primary, Liu, H., additional, Irwanto, A., additional, Fu, X.-A., additional, Li, Y., additional, Yu, G.-Q., additional, Yu, Y.-X., additional, Chen, M.-F., additional, Low, H.-Q., additional, Li, J.-H., additional, Bao, F.-F., additional, Foo, J.-N., additional, Bei, J.-X., additional, Jia, X.-M., additional, Liu, J., additional, Liany, H., additional, Wang, N., additional, Niu, G.-Y., additional, Wang, Z.-Z., additional, Shi, B.-Q., additional, Tian, H.-Q., additional, Liu, H.-X., additional, Ma, S.-S., additional, Zhou, Y., additional, You, J.-B., additional, Yang, Q., additional, Wang, C., additional, Chu, T.-S., additional, Liu, D.-C., additional, Yu, X.-L., additional, Sun, Y.-H., additional, Ning, Y., additional, Wei, Z.-H., additional, Chen, S.-L., additional, Chen, X.-C., additional, Zhang, Z.-X., additional, Liu, Y.-X., additional, Pulit, S.L., additional, Wu, W.-B., additional, Zheng, Z.-Y., additional, Yang, R.-D., additional, Long, H., additional, Liu, Z.-S., additional, Wang, J.-Q., additional, Li, M., additional, Zhang, L.-H., additional, Wang, H., additional, Wang, L.-M., additional, Xiao, P., additional, Li, J.-L., additional, Huang, Z.-M., additional, Huang, J.-X., additional, Li, Z., additional, Xiong, L., additional, Yang, J., additional, Wang, X.-D., additional, Yu, D.-B., additional, Lu, X.-M., additional, Zhou, G.-Z., additional, Yan, L.-B., additional, Shen, J.-P., additional, Zhang, G.-C., additional, Zeng, Y.-X., additional, de Bakker, P.I.W., additional, Chen, S.-M., additional, and Liu, J.-J., additional

Published
2013
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45. Amyloid- /Fyn-Induced Synaptic, Network, and Cognitive Impairments Depend on Tau Levels in Multiple Mouse Models of Alzheimer's Disease

Author

Roberson, E. D., primary, Halabisky, B., additional, Yoo, J. W., additional, Yao, J., additional, Chin, J., additional, Yan, F., additional, Wu, T., additional, Hamto, P., additional, Devidze, N., additional, Yu, G.-Q., additional, Palop, J. J., additional, Noebels, J. L., additional, and Mucke, L., additional

Published
2011
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