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From the discovery of giant magnetoresistance (GMR) to tunnel magnetoresistance (TMR), their subsequent application in large capacity hard disk drives (HDDs) greatly speeded up the information era over the past decades. However, the growing demand for big-data storage and processing is limited by the von-Neumann architecture due to the memory bottleneck and power dissipation. Taking advantage of nonvolatility, high speed, and low power, magnetic random access memory (MRAM) becomes a promising candidate to overcome this limitation through processing-in-memory (PIM) architectures. In this article, we provide an overview of existing technology and give a roadmap of spintronic devices for future energy-efficient computing and its relevant integration architectures. We begin with the fundamentals of Toggle-MRAM and spin-transfer torque (STT)-MRAM, which already have commercial applications. We then introduce spin-orbit torque (SOT), a critical mechanism to realize low-power data manipulation in the next generation of MRAM and summarize the recent experimental breakthroughs of field-free SOT switching schemes. Finally, we present MRAM-based PIM architectures and novel spintronic devices, provide an application outlook, and deliver the future development potential of energy-efficient computing systems.

The interplay of spin-transfer torque (STT) and spin-orbit torque (SOT) highlights the potential of current-induced magnetization reversal for the ultrahigh-speed and ultralow-power memory applications. However, the ultrafast field-free switching and its dynamic mechanism have not been clarified yet. Here, we experimentally demonstrate the sub-nanosecond field-free switching by the interplay of STT and SOT in perpendicular magnetic tunnel junctions (MTJs). The dynamic investigations of the STT and SOT switching reveal that the applied SOT current can highly decrease the incubation time and current density of STT, which leads to the achievement of ultra-fast switching. Besides, the timing scheme investigations of SOT and STT pulses are performed. The firstly applied SOT current further decreases the transition time of the magnetization switching, which could result from the different nucleation and motions of domains. The interplay and the timing operations of STT and SOT provide more flexible solutions for high-speed, large-scalability and energy efficient memory applications.

The perovskite oxide Sm0.5Sr0.5CoO3-δ (SSC) ceramic with nacre–like structure was prepared by tape casting, solid-state reaction, and laminating method. The optical property, thermal shock resistance, and the photothermal conversion performance of the normal bulk and nacre–like SSC ceramics were investigated. The results showed that the nacre-like structure SSC exhibited similar optical property with that of bulk SSC, yet with better thermal shock resistance due to the toughening effect attributed to SSC bricks pull-out and crack deflection along the interfaces. Moreover, under the irradiation of high concentration sunlight (21 W/cm2), the nacre-like SSC remained intact and could reach an equilibrium temperature of ~870 °C, while the normal bulk SSC cracked as soon as exposed to the high concentration sunlight. The nacre–like SSC ceramic developed in this work is a promising candidate for high temperature solar thermal application.

Blood pressure (BP) is a cardiovascular parameter which exhibits significant variability. Whilst continuous BP monitoring would be of significant clinical utility. This is particularly challenging outside the hospital environment. New wearable cuff-based and cuffless BP monitoring technologies provide some capacity, however they have a number of limitations including bulkiness, rigidity and discomfort, poor accuracy and motion artefact. Here, we report on a lightweight, user-friendly, non-invasive wearable cardiac sensing system based on deformation-insensitive conductive gold nanowire foam (G-foam) and pressure-sensitive resistive gold nanowire electronic skin (G-skin). The G-foam could serve as a new soft dry bioelectrode for electrocardiogram (ECG) monitoring; a new soft button-based G-skin design could avoid manual holding for continuous pulse recording. They could be integrated seamlessly with everyday bandage for facile wireless recording of ECG and artery pulses under real-word dynamic environments including walking, running, deep squatting, and jogging. Further machine learning algorithm was developed for estimation of systolic and diastolic BP, showing comparable accuracy to commercial cuff-based sphygmomanometer. The measured dynamic BP changes correlated well with the volunteer's daily activities, indicating the potential applications of our soft wearable systems for real-time diagnostics of cardiovascular functions in complex dynamic real-world setting.

We demonstrate in-plane field-free-switching spin-orbit torque (SOT) magnetic tunnel junction (MTJ) devices that are capable of low switching current density, fast speed, high reliability, and, most importantly, manufactured uniformly by the 200-mm-wafer platform. The performance of the devices is systematically studied, including their magnetic properties, switching behaviors, endurance and data retention. The successful integration of SOT devices within the 200-mm-wafer manufacturing platform provides a feasible way to industrialize SOT MRAMs. It is expected to obtain excellent performance of the devices by further optimizing the MTJ film stacks and the corresponding fabrication processes in the future.

In spite of advances in electronics and internet technologies, current healthcare remains hospital-centred. Disruptive technologies are required to translate state-of-art wearable devices into next-generation patient-centered diagnosis and therapy. In this review, recent advances in the emerging field of soft wearable materials and devices are summarized. A prerequisite for such future healthcare devices is the need of novel materials to be mechanically compliant, electrically conductive, and biologically compatible. It is begun with an overview of the two viable design strategies reported in the literatures, which is followed by description of state-of-the-art wearable healthcare devices for monitoring physical, electrophysiological, chemical, and biological signals. Self-powered wearable bioenergy devices are also covered and sensing systems, as well as feedback-controlled wearable closed-loop biodiagnostic and therapy systems. Finally, it is concluded with an overall summary and future perspective.

As an environmentally-friendly fresh water production method, solar water evaporation plays an important role in solving the shortage of fresh water. Recently, various kinds of solar absorbers have been developed. However, most of solar absorbers are hydrophilic for the sufficient water supply, and less attention has been paid to the effect of absorber’s wettability on the evaporation performance. Herein, the effect of wettability of photo-thermal films on the evaporation rates was investigated. The evaporation of the full-wetting film (0.99 kg m−2 h−1) increased by 5.3% compared to the semi-wetting film (0.94 kg m−2 h−1) at 1 kW m−2. Conversely, the evaporation of the full-wetting film (8.77 kg m−2 h−1) decreased by 8.5% compared to the semi-wetting film (9.58 kg m−2 h−1) at 13 kW m−2. The systematic test indicated that the full-wetting film exhibited high evaporation performance at low optical power densities (1–5 kW m−2), and the performance of the semi-wetting film was better at high optical power densities (9–13 kW m−2). This work provides a new avenue to achieve high evaporation performance by tuning the wettability at different application environments.

A novel CuAlMn/polymer/carbon nanomaterials multi-scale composite with damping capability was successfully prepared. These composite materials composed of a CuAlMn memory alloy foam skeleton and a polymer matrix, which was in turn reinforced with different carbon nanomaterials. Experiment results show that the loss factor of CuAlMn/polymer/CNT composite is above 0.1, while the loss factor of CuAlMn/polymer/(Au@CNT + CNF + GNS) composite is higher than 0.12 over the entire temperature range, with the highest value reaching about 0.15. Also, it can be seen that the storage modulus of CuAlMn/polymer composite is above 3500 MPa, while CuAlMn/polymer/(Au@CNT + CNF + GNS) composite is about 1000 MPa. The loss factor for CuAlMn/polymer/(Au@CNT + CNF + GNS) composite is highest, and the storage modulus of it is lowest. A three-phase model was introduced to analyze the damping mechanism of the composite. The results indicate that the damping performance of the prepared composites is mainly affected by interfacial loss, which can be effectively improved by increasing the mismatch of elastic modulus near the interface and/or increasing the interfacial area. On these bases, the optimal performance of the composite material was predicted by calculation and simulation. This multi-scale composite offers a tremendously promising future, which needs further thorough exploration.

The effect of drought stress on the antioxidant system and membrane lipid peroxidation in flag leaves of a super-hybrid rice variety (Liang-You-Pei-Jiu, LYPJ) during the grain filling period was studied. During prophase of water deficit up to day 6 at relative soil water content (RSWC) 88 %, 81 %, 69 %, the superoxide dismutase (SOD) activity descended slightly, but the activities of peroxidase (POD) and catalase (CAT) ascended rapidly. The content of ascorbic acid (AsA) and glutathione (GSH) decreased. The production rate of superoxide radical (O2−), the contents of hydrogen peroxide (H2O2) and malondialdehyde (MDA) were maintained in a low level (0.3481 nmolO2− mg−1 protein min−1, 170.17 μmol g−1 FW, 1.467 nmol g−1 FW, at day 6, respectively). The total membrane lipids and index of unsaturated fatty acids (IUFA) did not change obviously. Thereafter (day 9, 12, with 52 %, 28 %, respectively RSWC), the activities of these enzymes declined significantly, while the content of AsA + GSH showed a reverse tendency. However, O2− production rate, the contents of H2O2 + MDA also increased rapidly. As a result, the total membrane lipids and IUFA dramatically decreased. The results indicated that the whole protect system was destructed seriously; any single protective component could not resist the damage caused by drought stress.