Search

Synthetic antiferromagnet (SAF) with high thermal stability, ultra‐fast spin dynamics, and highly efficient spin‐orbit torque switching has great application potential in neuromorphic computing hardware. However, two challenges, the weakening of Hall signal in the remanent state and the need for a large auxiliary magnetic field for perpendicular magnetization switching, greatly limit the advantages of SAF in neuromorphic computing. In this work, both the enhanced anomalous Hall resistance and magnetic‐field‐free perpendicular magnetization switching are achieved by using oblique sputtering to fabricate the Pt/CoPt/Ru/CoTb SAF with strong interlayer exchange coupling and magnetic moment compensation. The fabricated SAF as synapse shows nearly linear, nonvolatile multistate plasticity, and as neuron exhibits a nonlinear sigmoid activation function, which are used to construct a fully connected neural network with a remarkable 97.0–98.1% recognition rate for the handwritten digits. Additionally, SAF serving as spike‐timing‐dependent plasticity synapse is used to construct an adaptive, unsupervised learning spiking neural network, and achieve an 87.0% accuracy in handwritten digit recognition. The findings exhibit the promise of SAFs as specialized hardware for high‐performance neuromorphic computing, offering high recognition rates and low power consumption. [ABSTRACT FROM AUTHOR]

This study aimed to establish a population pharmacokinetic (PopPK) model using data from 2 clinical trials of zimberelimab, evaluate the pharmacokinetics (PKs) of zimberelimab, explore the feasibility of 360 mg once every 3 weeks (Q3W) and 480 mg once every 4 weeks (Q4W) as alternative dosage regimens, and analyze the exposure‐response relationship of the efficacy and safety of zimberelimab for advanced tumors. The PKs of zimberelimab were described using the 2‐compartment model with time‐dependent nonlinear elimination. The prediction‐corrected visual predictive check was used to evaluate the model's predictive value on blood drug concentrations. In total, 2165 PK observations from 321 participants were included. The PopPK model demonstrated a high level of concordance between the observed data and the predicted values, indicative of a robust fit to the PK data of zimberelimab. The PK variables were similar for the 240 mg once every 2 weeks, 360 mg Q3W, and 480 mg Q4W regimens. No covariates significantly affecting the PK variables in the final model were found. The exposure variables of zimberelimab have no obvious correlations with efficacy and safety, and 360 mg Q3W and 480 mg Q4W are worthy of further study. This study establishes a PopPK model and analyzes the exposure‐response relationship of zimberelimab, which helps to explore the potential for alternative dosing regimens and offers a foundation for optimizing therapeutic strategies for advanced cancer patients through simulation‐based methods. [ABSTRACT FROM AUTHOR]

In the field of information hardware security, random variations obtained during device manufacturing process play a key role in generating unique and unclonable security keys. Existing physical unclonable functions (PUFs) utilizing these static randomnesses usually exhibit static challenge‐response pairs, which cannot be refreshed and limit their application prospects. Here, it is demonstrated that purely electrical controllable spin–orbit torque (SOT)‐based reconfigurable PUFs (rPUFs) can be realized in Pt/IrMn/Co/Ru/CoPt heterojunctions. By applying current pulses along two orthogonal directions, both the exchange bias between IrMn and Co and the SOT switching polarity (clockwise or counterclockwise) of perpendicularly magnetized CoPt can be reversibly controlled, which enables the realization of four rPUF states within a single device. By taking advantages of the sample growth and micro‐nanofabrication induced variations in the critical switching current density of SOT‐driven magnetization switching, the rPUF device with relatively good uniqueness and low bit error rate is achieved. Our work provides an approach to information hardware security and broadens the application of spintronics. [ABSTRACT FROM AUTHOR]

In order to study the fracture behavior of hydraulic concrete, wedge splitting tests are performed on notched cubic concrete specimens with different crack-depth ratios (0.3, 0.4, and 0.5). Meanwhile, acoustic emission and the digital image correlation method were used to monitor the crack propagation. Test results show that the initiation toughness of the hydraulic concrete specimen is independent of the crack-depth ratio. As the crack-depth ratio increases, the fracture toughness, the fracture energy, and the critical crack length decrease. The AE cumulative counts and hits can reflect not only the four-stages fracture process of hydraulic concrete but also the boundary effect of hydraulic concrete. The acoustic emission b value can reflect the two stages of postpeak damage of the hydraulic concrete. The length of fictitious crack, the propagation velocity of macrocrack and effective crack length decrease with the increase of the initial notch depth ratio. The effective crack length increases with the increase in the maximum aggregate size, and the growth time increases with the maximum aggregate size and an effective height of the specimen. [ABSTRACT FROM AUTHOR]

Flexible synaptic devices that emulate biological synapses are the key to developing wearable intelligent equipment. However, there are still challenges to achieving multiple synaptic functions in flexible synaptic devices and realizing large‐scale production of synaptic devices. Herein, a flexible synaptic transistor on polyimide substrate is designed and fabricated using a solid‐state electrolyte gate and a VO2 Mott insulator thin film channel. Four orders conductance modulation is obtained in the VO2 thin film channel across the metal‐insulator transition. Several essential synaptic behaviors, including potentiation, depression, and short‐term/long‐term plasticity, are successfully demonstrated in this flexible synaptic device. More importantly, this synaptic transistor exhibits high cycling stability and good tolerance to bending deformation. A simulated artificial neural network built from this synaptic device achieves high recognition accuracy of 98% in the flat state and 92% in the bending state. In addition, this flexible device is fabricated on polyimide substrate by magnetron sputtering method, which has low cost and is compatible with modern semiconductor technology. This work can pave the way for large‐scale production of flexible synaptic Mott transistor devices. [ABSTRACT FROM AUTHOR]

To electrically control magnetic properties of material is promising toward spintronic applications, where the investigation of carrier doping effects on antiferromagnetic (AFM) materials remains challenging due to their zero net magnetization. In this work, the authors find electron doping dependent variation of magnetic orders of a 2D AFM insulator NiPS3, where doping concentration is tuned by intercalating various organic cations into the van der Waals gaps of NiPS3 without introduction of defects and impurity phases. The doped NiPS3 shows an AFM‐ferrimagnetic (FIM) transition at a doping level of 0.2–0.5 electrons/cell and a FIM‐AFM transition at a doping level of ≥0.6 electrons/cell. The authors propose that the found phenomenon is due to competition between Stoner exchange dominated inter‐chain ferromagnetic order and super‐exchange dominated AFM order at different doping level. The studies provide a viable way to exploit correlation between electronic structures and magnetic properties of 2D magnetic materials for realization of magnetoelectric effect. [ABSTRACT FROM AUTHOR]

Fully electrical manipulation of magnetism, preferably through spin current, is highly desired to achieve energy-efficient, nonvolatile, and programmable spin logic devices. It is demonstrated in this study that in a single Pt/IrMn/ Co/Ru/CoPt heterojunction, all 16 Boolean logic functions can be realized in a purely electrical way, relying on electrical manipulation of magnetic-field-free spin-orbit torque (SOT) switching. By applying current pulses along with two orthogonal directions, the exchange bias between IrMn and Co, and the SOT switching polarity (clockwise or counterclockwise) of perpendicularly magnetized CoPt, can be reversibly controlled, enabling complete spin logic within a single nonvolatile memory. This study makes a significant step towards practical electrical programmable spin logic devices. [ABSTRACT FROM AUTHOR]

Voltage‐driven oxygen ion migration in ferromagnetic metal/oxide heterostructures offers a highly effective means to tailor emergent interfacial functionalities. In heterojunctions with a core structure of Pt/Co/CoO/TiO2 (TaOx), it is demonstrated that exchange coupling of magnetic moments across the Co/CoO interface provides an extra source to stabilize the perpendicular magnetic anisotropy (PMA). Moreover, the strength of this interfacial coupling can be reversibly controlled through voltage‐driven oxygen ion migration at the Co/CoO interface, resulting in electrical‐field‐controllable PMA. In combination with the spin current generated from Pt, it is revealed that the spin‐orbit torque (SOT) switching of the perpendicular magnetization of Co can be turned ON/OFF by electrical field. Tunable PMA and SOT switching makes heavy metal/ferromagnetic metal/antiferromagnetic oxide heterojunctions a promising candidate to future voltage‐controlled, ultralow‐power, and high‐density spintronics devices. [ABSTRACT FROM AUTHOR]

The article offers information on nonlinear optimization values by demonstrating several investment theories which include utility theory, capital market theory, and modern portfolio theory. It notes that both problems in utility maximization and portfolio optimization can be resolved. It cites, as an example, the utility maximization among investors which accounts to the level of risk aversion.

Spintronics: Electrical Control of Perpendicular Magnetic Anisotropy and Spin-Orbit Torque-Induced Magnetization Switching (Adv. In article number 1900782, Yufeng Tian and co-workers demonstrate that exchange coupling of magnetic moments across the Co/CoO interface provides an extra source of stabilization for the perpendicular magnetic anisotropy (PMA) in heterojunctions with a core structure of Pt/Co/CoO/TiO2 (TaOx). The inside cover image shows a representation of this system, with the background showing a Pt/Co/CoO/oxide/Pt cell crossbar array on a chip and the center showing an enlarged view. [Extracted from the article]

Emerging nonvolatile multilevel memory devices have been regarded as a promising solution to meet the increasing demand of high‐density memory with low‐power consumption. In particular, decimal system of the new computers instead of binary system could be developed if ten nonvolatile states are realized. Here, a general remanent magnetism engineering method is proposed for realizing multiple reliable magnetic and resistance states, not depending on a specific material or device structure. Especially, as a proof‐of‐concept demonstration, ten states of nonvolatile memory based on the manipulation of ferromagnetic remanent magnetization have been revealed in both Co/Pt magnetic multilayers with strong perpendicular magnetic anisotropy and MgO‐based magnetic tunneling junctions at room temperature. Considering ferromagnets have been one of the key factors that enabled the information revolution from its inception, this state‐of‐the‐art remanent magnetism engineering approach has a very broad application prospect in the field of spintronics. Ten states of nonvolatile memory are demonstrated in both Co/Pt magnetic multilayers and MgO‐based magnetic tunneling junctions based on the manipulation of ferromagnetic remanent magnetization. Moreover, this remanent magnetization engineering method could be adapted to other systems containing multidomain ferromagnets. Hence, this method provides an attractive way toward multilevel nonvolatile memory devices. [ABSTRACT FROM AUTHOR]