Efficient current-induced spin torques and field-free magnetization switching in a room-temperature van der Waals magnet

The discovery of magnetism in van der Waals (vdW) materials has established unique building blocks for the research of emergent spintronic phenomena. In particular, owing to their intrinsically clean surface without dangling bonds, the vdW magnets hold the potential to construct a superior interface that allows for efficient electrical manipulation of magnetism. Despite several attempts in this direction, it usually requires a cryogenic condition and the assistance of external magnetic fields, which is detrimental to the real application. Here, we fabricate heterostructures based on Fe3GaTe2 flakes that possess room-temperature ferromagnetism with excellent perpendicular magnetic anisotropy. The current-driven non-reciprocal modulation of coercive fields reveals a high spin-torque efficiency in the Fe3GaTe2/Pt heterostructures, which further leads to a full magnetization switching by current. Moreover, we demonstrate the field-free magnetization switching resulting from out-of-plane polarized spin currents by asymmetric geometry design. Our work could expedite the development of efficient vdW spintronic logic, memory and neuromorphic computing devices

Carbon materials toward efficient potassium storage: Rational design, performance evaluation and potassium storage mechanism

Potassium-ion batteries (PIBs) are potential “Beyond Li-ion Batteries” candidates for their resource advantage and low standard electrode potential. To date, the research on PIBs is in its early stages, the most urgent task is to develop high-performance electrode materials and reveal their potassium storage mechanism. For PIBs anode materials, carbon with tunable microstructure, excellent electrochemical activity, nontoxicity and low price is considered as one of the most promising anode materials for commercialization. Although some breakthrough works have emerged, the overall electrochemical performance of the reported carbon anode is still far away from practical application. Herein, we carry out a comprehensive overview of PIBs carbon anode in terms of three aspects of rational design of structure, performance evaluation criteria and characterization of potassium storage mechanism. First, the regulation mechanism of key structural features of carbon anode on its potassium storage performance and the representative structural regulation strategies are introduced. Then, in view of the undefined performance evaluation criteria of PIBs carbon anode, a reference principle for evaluating the potassium storage performance of carbon anode is proposed. Finally, the advanced characterization techniques for the potassium storage mechanism of carbon anode are summarize. This review aims to provide guidance for the development of practical PIBs anode

Graphene-based nanocomposites for energy storage and conversion in lithium batteries, supercapacitors and fuel cells

Due to their unique properties, together with their ease of synthesis and functionalization, graphene-based materials have been showing great potential in energy storage and conversion. These hybrid structures display excellent material characteristics, including high carrier mobility, faster recombination rate and long-time stability. In this review, after a short introduction to graphene and its derivatives, we summarize the recent advances in the synthesis and applications of graphene and its derivatives in the fields of energy storage (lithium ion, lithium-air, lithium-sulphur batteries and supercapacitors) and conversion (oxygen reduction reaction for fuel cells). This article further highlights the working principles and problems hindering the practical applications of graphene-based materials in lithium batteries, supercapacitors and fuel cells. Future research trends towards new methodologies to the design and the synthesis of graphene-based nanocomposite with unique architectures for electrochemical energy storage and conversion are also proposed. The Royal Society of Chemistry

New Types of Magnetic Nanoparticles for Stimuli‐Responsive Theranostic Nanoplatforms

Abstract Magnetic nanomaterials have played a crucial role in promoting the application of nanotechnology in the biomedical field. Although conventional magnetic nanomaterials such as iron oxide nanoparticles (NPs) are used as biosensors, drug delivery vehicles, diagnostic and treatment agents for several diseases, the persistent pursuit of high‐performance technologies has prompted researchers to continuously develop new types of magnetic nanomaterials such as iron carbide NPs. Considering their potential application in biomedicine, magnetic NPs responsive to exogenous or endogenous stimuli are developed, thereby enhancing their applicability in more complex versatile scenarios. In this review, the synthesis and surface modification of magnetic NPs are focused, particularly iron carbide NPs. Subsequently, exogenous and endogenous stimuli‐responsive magnetic NP‐based theranostic platforms are introduced, particularly focusing on nanozyme‐based technologies and magnetic NP‐mediated immunotherapy, which are emerging stimuli‐responsive treatments. Finally, the challenges and perspectives of magnetic NPs to accelerate future research in this field are discussed

Magnetic nanomaterials: undamentals, synthesis and applications

Timely and comprehensive, this book presents recent advances in magnetic nanomaterials research, covering the latest developments, including the design and preparation of magnetic nanoparticles, their physical and chemical properties as well as their applications in different fields, including biomedicine, magnetic energy storage, wave–absorbing and water remediation. By allowing researchers to get to the forefront developments related to magnetic nanomaterials in various disciplines, this is invaluable reading for the nano, magnetic, energy, medical, and environmental communities

Liquid-Phase Templateless Synthesis of Pt-on-Pd_0.85Bi_0.15 Nanowires and PtPdBi Porous Nanoparticles with Superior Electrocatalytic Activity

This article reports the synthesis of Pt-on-Pd_0.85Bi_0.15 nanowires (NWs) and PtPdBi porous nanoparticles (PNPs) by a facile, one-pot, wet-chemical, and templateless method in the presence of oleylamine (OAm) and NH₄Br. The relationship between the morphology and composition in the PtPdBi trimetallic system was systematically studied. Interestingly, it is verified that adding only 5% Bi will produce Pd NWs, which offers a novel approach to synthesize Pd NWs in the oil phase without any template. On the basis of the fact of synthesizing Pd_0.85Bi_0.15 NWs, Pt-on-Pd_0.85Bi_0.15 NWs with hetero-nanostructures were successfully synthesized by a one-step method. Furthermore, the number of Pt nanobranches for Pt-on-Pd_0.85Bi_0.15 NWs could be easily controlled via simply changing the synthetic parameters, which could tune the catalytic properties. PtPdBi PNPs were obtained by the acid pickling of PtPdBi₂ intermetallic compounds. Most importantly, a catalytic study indicates that the as-obtained Pt-on-Pd_0.85Bi_0.15 NWs and PtPdBi PNPs exhibited much higher electrocatalytic activity and durability for the oxygen reduction reaction (ORR) than the commercial Pt/C catalyst. We expect that this work will provide a promising strategy for the development of efficient ORR electrocatalysts and can also be extended to the preparation of other nanowires or hetero-nanostructures with desirable functions