Effect of antiferromagnetic coupling at interfaces on magnetic properties of Gd/CoFeTaB multilayers

In this work, a multilayer structure composed of Gd and CoFeTaB was prepared by magnetron sputtering, and the effect of annealing temperatures on magnetic properties of the multilayer structure are investigated. The existence of interfacial antiferromagnetic coupling in this system was proved by analysis of microstructure, magnetic characteristics, and magnetic resonance characteristics. The preparation of artificial multilayer antiferromagnetic structure with weak stray fields was demonstrated, which provides a shortcut for spintronics application

Magnon-bandgap controllable artificial domain wall waveguide

In this paper, a magnon-bandgap controllable artificial domain wall waveguide is proposed by means of micromagnetic simulation. By the investigation of the propagation behavior and dispersion relationship of spin waves in artificial domain wall waveguides, it is found that the nonreciprocal propagation of spin waves in the artificial domain walls are mainly affected by the local effective exchange field, and the magnon bandgap can be controlled by changing the maximum value of the effective exchange field. In addition, it is observed that the artificial domain wall waveguides are structurally more stable than the natural domain wall waveguides under the same spin wave injection conditions, and the magnon bandgap of the artificial domain wall waveguides can be adjusted by its width and magnetic anisotropy parameters. The bandgap controllable artificial domain wall scheme is beneficial to the miniaturization and integration of magnon devices and can be applied to future magnonic technology as a novel frequency filter

Role of non-thermal electrons in ultrafast spin dynamics of ferromagnetic multilayer

Understanding of ultrafast spin dynamics is crucial for future spintronic applications. In particular, the role of non-thermal electrons needs further investigation in order to gain a fundamental understanding of photoinduced demagnetization and remagnetization on a femtosecond time scale. We experimentally demonstrate that non-thermal electrons existing in the very early phase of the photoinduced demagnetization process play a key role in governing the overall ultrafast spin dynamics behavior. We simultaneously measured the time-resolved reflectivity (TR-R) and the magneto-optical Kerr effect (TR-MOKE) for a Co/Pt multilayer film. By using an extended three-temperature model (E3TM), the quantitative analysis, including non-thermal electron energy transfer into the subsystem (thermal electron, lattice, and spin), reveals that energy flow from non-thermal electrons plays a decisive role in determining the type I and II photoinduced spin dynamics behavior. Our finding proposes a new mechanism for understanding ultrafast remagnetization dynamics. © 2020, The Author(s).1

Dual Antiplatelet Therapy vs Alteplase for Patients With Minor Nondisabling Acute Ischemic Stroke

Importance Intravenous thrombolysis is increasingly used in patients with minor stroke, but its benefit in patients with minor nondisabling stroke is unknown. Objective To investigate whether dual antiplatelet therapy (DAPT) is noninferior to intravenous thrombolysis among patients with minor nondisabling acute ischemic stroke. Design, Setting, and Participants This multicenter, open-label, blinded end point, noninferiority randomized clinical trial included 760 patients with acute minor nondisabling stroke (National Institutes of Health Stroke Scale [NIHSS] score ≤5, with ≤1 point on the NIHSS in several key single-item scores; scale range, 0-42). The trial was conducted at 38 hospitals in China from October 2018 through April 2022. The final follow-up was on July 18, 2022. Interventions Eligible patients were randomized within 4.5 hours of symptom onset to the DAPT group (n = 393), who received 300 mg of clopidogrel on the first day followed by 75 mg daily for 12 (±2) days, 100 mg of aspirin on the first day followed by 100 mg daily for 12 (±2) days, and guideline-based antiplatelet treatment until 90 days, or the alteplase group (n = 367), who received intravenous alteplase (0.9 mg/kg; maximum dose, 90 mg) followed by guideline-based antiplatelet treatment beginning 24 hours after receipt of alteplase. Main Outcomes and Measures The primary end point was excellent functional outcome, defined as a modified Rankin Scale score of 0 or 1 (range, 0-6), at 90 days. The noninferiority of DAPT to alteplase was defined on the basis of a lower boundary of the 1-sided 97.5% CI of the risk difference greater than or equal to −4.5% (noninferiority margin) based on a full analysis set, which included all randomized participants with at least 1 efficacy evaluation, regardless of treatment group. The 90-day end points were assessed in a blinded manner. A safety end point was symptomatic intracerebral hemorrhage up to 90 days. Results Among 760 eligible randomized patients (median [IQR] age, 64 [57-71] years; 223 [31.0%] women; median [IQR] NIHSS score, 2 [1-3]), 719 (94.6%) completed the trial. At 90 days, 93.8% of patients (346/369) in the DAPT group and 91.4% (320/350) in the alteplase group had an excellent functional outcome (risk difference, 2.3% [95% CI, −1.5% to 6.2%]; crude relative risk, 1.38 [95% CI, 0.81-2.32]). The unadjusted lower limit of the 1-sided 97.5% CI was −1.5%, which is larger than the −4.5% noninferiority margin (P for noninferiority <.001). Symptomatic intracerebral hemorrhage at 90 days occurred in 1 of 371 participants (0.3%) in the DAPT group and 3 of 351 (0.9%) in the alteplase group. Conclusions and Relevance Among patients with minor nondisabling acute ischemic stroke presenting within 4.5 hours of symptom onset, DAPT was noninferior to intravenous alteplase with regard to excellent functional outcome at 90 days. Trial Registration ClinicalTrials.gov Identifier: NCT0366141

Synthesis of 5-Alkoxythieno[2,3-e][1,2,4]triazolo[4,3-c]pyrimidine Derivatives and Evaluation of Their Anticonvulsant Activities

This work concerns the design and synthesis of novel, substituted 5-alkoxythieno[2,3-e][1,2,4]triazolo[4,3-c]pyrimidine derivatives 5a–p prepared from 3-amino-2-thiophenecarboxylic acid methyl ester. The final compounds were screened for their in vivo anticonvulsant activity using maximal electroshock (MES) and subcutaneous pentylenetetrazole (scPTZ) tests. Neurotoxicity (NT) was tested using a rotarod test. The structure-anticonvulsant activity relationship analysis revealed that the most effective structural motif involves a substituted phenol, especially when substituted with a single chlorine, fluorine or trifluoromethyl group (at the meta-position), or two chlorine atoms. These molecules possessed high activity according to the MES and scPTZ models. Quantitative assessment of the compounds after intraperitoneal administration in mice showed that the most active compound was 5-[3-(trifluoromethyl)phenoxy]thieno[2,3-e] [1,2,4]triazolo[4,3-c]pyrimidine (5o) with ED50 values of 11.5 mg/kg (MES) and 58.9 mg/kg (scPTZ). Furthermore, compound 5o was more effective in the MES and scPTZ tests than the well-known anticonvulsant drugs carbamazepine and ethosuximide

Unidirectional switching of magnetic vortex core confined in a cylindrical nanocavity

Ultrafast unidirectional reversal of magnetic vortex core confined in a cylindrical nanocavity is numerically investigated using micromagnetic simulations for the permalloy nanodisk. The excited modes (convergence/divergence) of the core motion are modulated differently by the cavity, depending on the dimension of the cavity, which is the main reason for the unidirectional vortex polarization switching. Assisted with the cavity, the core can be reversed well below 200 ps with less than 10 mT external magnetic field and over a wide range of field frequency. In particular, the core can be selectively switched by varying the dimension of the cylindrical cavity. (C) 2019 The Japan Society of Applied Physics11Nsciescopu

Asymmetric dynamic behaviors of magnetic domain wall in trapezoid-cross-section nanostrip

Field-driven magnetic domain wall propagation in ferromagnetic nanostrips with trapezoidal cross section has been systematically investigated by means of micromagnetic simulation. Asymmetric dynamic behaviors of domain wall, depending on the propagation direction, were observed under an external magnetic field. When the domain walls propagate in the opposite direction along the long axis of the nanostrip, the Walker breakdown fields as well as the average velocities are different. The asymmetric landscape of demagnetization energies, which arises from the trapezoidal geometry, is the main origin of the asymmetric propagation behavior. Furthermore, a trapezoid-cross-section nanostrip will become a nanotube if it is rolled artificially along its long axis, and thus a two-dimensional transverse domain wall will become a three-dimensional one. Interestingly, it is found that the asymmetric behaviors observed in two-dimensional nanostrips with trapezoidal cross section are similar with some dynamic properties occurring in three-dimensional nanotubes. © 2020 Chinese Physical Society and IOP Publishing Ltd.1