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van der Waals (vdW) materials exhibit great potential in spintronics, arising from their excellent spin transportation, large spin–orbit coupling, and high‐quality interfaces. The recent discovery of intrinsic vdW antiferromagnets and ferromagnets has laid the foundation for the construction of all‐vdW spintronic devices, and enables the study of low‐dimensional magnetism, which is of both technical and scientific significance. In this review, several representative families of vdW magnets are introduced, followed by a comprehensive summary of the methods utilized in reading out the magnetic states of vdW magnets. Thereafter, it is shown that various electrical, mechanical, and chemical approaches are employed to modulate the magnetism of vdW magnets. Finally, the perspective of vdW magnets in spintronics is discussed and an outlook of future development direction in this field is also proposed. van der Waals (vdW) magnets are very important in the fields of low‐dimensional physics and spintronics. A thorough summary of the latest advances in this area is provided, including the material families, various methods used in the detection and modulation of their magnetism, their potential applications in spintronics, and the opportunities and challenges in the future.

Two-dimensional (2D) dielectrics, integrated with high-mobility semiconductors, show great promise to overcome the scaling limits in miniaturized integrated circuits. However, the 2D dielectrics explored to date still face the challenges of low crystallinity, diminished dielectric constant, and the lack of effective synthesis methods. Here, we report the controllable synthesis of ultra-thin gadolinium oxychloride (GdOCl) nanosheets via a chloride hydrate-assisted chemical vapor deposition (CVD) method. The resultant GdOCl nanosheets display good dielectric properties, including a high dielectric constant (high-κ) of 15.3, robust breakdown field strengths ( E bd ) exceeding 9.9 MV/cm, and minimal gate leakage currents of approximately 10 −6 A/cm 2 . The top-gated GdOCl/MoS 2 field-effect transistors (FETs) exhibit commendable switch characteristics, a negligible hysteresis of ~5 mV and a subthreshold swing down to 67.9 mV dec −1 . The GdOCl/MoS 2 FETs can also be employed to construct functional logic gates. Our study underscores the significant potential of the 2D GdOCl dielectric for innovative high-speed operated nanoelectronic devices. van der Waals dielectric materials are required to promote the industrialization of miniaturized 2D electronics. Here, the authors report the growth of GdOCl single crystals with a dielectric constant of 15.3 and equivalent oxide thickness down to 1.3 nm, showing their application for the realization of high-performance 2D MoS 2 transistors.

Spintronic devices based on antiferromagnetic (AFM) materials hold the promise of fast switching speeds and robustness against magnetic fields1–3. Different device concepts have been predicted4,5 and experimentally demonstrated, such as low-temperature AFM tunnel junctions that operate as spin-valves6, or room-temperature AFM memory, for which either thermal heating in combination with magnetic fields7 or Néel spin–orbit torque8 is used for the information writing process. On the other hand, piezoelectric materials were employed to control magnetism by electric fields in multiferroic heterostructures9–12, which suppresses Joule heating caused by switching currents and may enable low-energy-consuming electronic devices. Here, we combine the two material classes to explore changes in the resistance of the high-Néel-temperature antiferromagnet MnPt induced by piezoelectric strain. We find two non-volatile resistance states at room temperature and zero electric field that are stable in magnetic fields up to 60 T. Furthermore, the strain-induced resistance switching process is insensitive to magnetic fields. Integration in a tunnel junction can further amplify the electroresistance. The tunnelling anisotropic magnetoresistance reaches ~11.2% at room temperature. Overall, we demonstrate a piezoelectric, strain-controlled AFM memory that is fully operational in strong magnetic fields and has the potential for low-energy and high-density memory applications.

Low-symmetry two-dimensional (2D) materials, with unique in-plane direction-dependent optical, electrical, and thermoelectric properties, have been intensively studied for their potential application values in advanced electronic and optoelectronic devices. However, since anisotropic 2D materials are highly sensitive to the environmental factors, researches on their high-performance field-effect transistors (FETs) are still limited. Here, we report a high-performance SnSe FET based on a van der Waals (vdWs) heterostructure of SnSe encapsulated in hexagonal boron nitride ( h BN) together with graphene contacts. The device exhibits a high on/off ratio exceeding 1 × 10 9 , and a carrier mobility of 118 cm 2 ·V −1 ·s −1 . Our work highlights low-symmetry 2D SnSe holds potential to be used for designing excellent electronic devices.

Anisotropic materials are of considerable interest because of their unique combination of polarization- or direction-dependent electrical, optical, and thermoelectric properties. Low-symmetry two-dimensional （2D） materials formed by van der Waals stacking of covalently bonded atomic layers are inherently anisotropic. Layered SnSe exhibits a low degree of lattice symmetry, with a distorted NaC1 structure and an in-plane anisotropy. Here we report a systematic study of the in-plane anisotropic properties in layered SnSe, using angle-resolved Raman scattering, optical absorption, and electrical transport studies. The optical and electrical characterization was direction-dependent, and successfully identified the crystalline orientation in the layered SnSe. Furthermore, the dependence of Raman-intensity anisotropy on the SnSe flake thickness and the excitation wavelength were investigated by both experiments and theoretical calculations. Finally, the electrical transport studies demonstrated that few-layer SnSe field- effect transistors （FETs） have a large anisotropic ratio of carrier mobility （N 5.8） bet- ween the armchair and zigzag directions, which is a record high value reported for 2D anisotropic materials. The highly-anisotropic properties of layered SnSe indicate considerable promise for anisotropic optics, electronics, and optoelectronics.

The exchange bias effect is extremely expected in 2D van der Waals (vdW) ferromagnetic (FM)/antiferromagnetic (AFM) heterostructures due to the high‐quality interface. CrOCl possesses strong magnetic anisotropy at 2D limit, and is an ideal antiferromagnet for constructing FM/AFM heterostructures to explore the exchange bias effect. Here, the exchange bias effect in Fe3GeTe2 (FGT)/CrOCl heterostructures through both anomalous Hall effect (AHE) and reflective magnetic circular dichroism (RMCD) measurements is studied. In the AHE measurements, the exchange bias field (HEB) at 3 K exhibits a distinct increase from ≈150 Oe to ≈450 Oe after air exposure, and such variation is attributed to the formation of an oxidized layer in FGT by analyzing the cross‐sectional microstructure. The HEB is successfully tuned by changing the FGT/CrOCl thickness and the cooling field. Furthermore, a larger HEB of ≈750 Oe at 1.7 K in FGT/CrOCl heterostructure through RMCD measurements is observed, and it is proposed that the larger HEB in RMCD measurements is related to the distribution of uncompensated spins at the interface. This work reveals several intriguing phenomena of the exchange bias effect in 2D vdW magnetic systems, which paves the way for the study of related spintronic devices. The exchange bias effect in ferro‐/antiferromagnetic Fe3GeTe2 (FGT)/CrOCl heterostructure is thoroughly studied through anomalous Hall effect and reflective magnetic circular dichroism (RMCD) measurements. The bias field (HEB) reveals anomaly increase with the presence of an oxidized layer in FGT. The larger HEB in the RMCD measurements can be related to the distribution of uncompensated spins.

All ferromagnetic materials show deterioration of magnetism-related properties such as magnetization and magnetostriction with increasing temperature, as the result of gradual loss of magnetic order with approaching Curie temperature T C . However, technologically, it is highly desired to find a magnetic material that can resist such magnetism deterioration and maintain stable magnetism up to its T C , but this seems against the conventional wisdom about ferromagnetism. Here we show that a Fe–Ga alloy exhibits highly thermal-stable magnetization up to the vicinity of its T C , 880 K. Also, the magnetostriction shows nearly no deterioration over a very wide temperature range. Such unusual behaviour stems from dual-magnetic-phase nature of this alloy, in which a gradual structural-magnetic transformation occurs between two magnetic phases so that the magnetism deterioration is compensated by the growth of the ferromagnetic phase with larger magnetization. Our finding may help to develop highly thermal-stable ferromagnetic and magnetostrictive materials. Magnetism deterioration is usually expected in all ferromagnetic materials with increasing temperature. Here, Ma et al . report a Fe-Ga alloy with highly thermal-stable magnetization up to 880 K and with nearly no deterioration over a wide temperature range in magnetostriction.

Magnetic skyrmions with nontrivial topologies have great potential to serve as memory cells in novel spintronic devices. Small skyrmions were theoretically and experimentally confirmed to be generated under the influence of external fields in ferrimagnetic films via Dzyaloshinskii–Moriya interactions (DMIs). However, this topological state has yet to be verified in ferrimagnetic crystals, especially in the absence of external fields and DMIs. Here, spontaneous biskyrmions were directly observed in the Tb0.2Gd0.8Co2 ferrimagnetic crystal with a Kagome lattice using Lorentz transmission electron microscopy. The high-density biskyrmions exhibited a small size (approximately 50 nm) over a wide temperature range, were closely related to subtle magnetic interaction competition, and coexisted with some broken stripes that could be easily converted into zero-field biskyrmions by utilizing proper field-cooling manipulation. These results can be used to establish a platform for investigating functional sub-50-nm skyrmions in ferrimagnetic crystals and to facilitate advanced applications in magnetic devices.Revolutionising Spintronics: Zero-Field Biskyrmions in Ferrimagnetic Kagome LatticeScientists have found a new method to control small skyrmions, which are tiny magnetic patterns, in ferrimagnetic materials (materials that have a net magnetic moment even without an external magnetic field arising from the two opposite magnetic sublattices). The research, led by S.L. Zuo and K.M. Qiao, revealed that these skyrmions can be maintained in ferrimagnetic materials without requiring an external magnetic field. The researchers used a technique called Lorentz transmission electron microscopy to observe the skyrmions in a specific ferrimagnetic crystal, Tb0.2Gd0.8Co2. They discovered that the skyrmions remained stable across a broad temperature range and could be easily controlled by altering the temperature or applying a minor magnetic field. This finding could be crucial for the creation of future spintronic devices, devices that use the rotation of electrons to store and process data.This summary was initially drafted using artificial intelligence, then revised and fact-checked by the author.

The electrical outputs of single-layer antiferromagnetic memory devices relying on the anisotropic magnetoresistance effect are typically rather small at room temperature. Here we report a new type of antiferromagnetic memory based on the spin phase change in a Mn-Ir binary intermetallic thin film at a composition within the phase boundary between its collinear and noncollinear phases. Via a small piezoelectric strain, the spin structure of this composition-boundary metal is reversibly interconverted, leading to a large nonvolatile room-temperature resistance modulation that is two orders of magnitude greater than the anisotropic magnetoresistance effect for a metal, mimicking the well-established phase change memory from a quantum spin degree of freedom. In addition, this antiferromagnetic spin phase change memory exhibits remarkable time and temperature stabilities, and is robust in a magnetic field high up to 60 T. Antiferromagnets have a variety of attractive features such as rapid operation, lack of stray fields, and insensitivity to external perturbations, that make an exciting prospect for memory and computing applications. Unfortunately, readout of the antiferromagnetic state is challenging. Here, Yan, Mao and coauthors demonstrate an antiferromagnet that can be switched between antiferromagnetic phases via piezoelectric strain with a large difference in the resistance between the two antiferromagnetic phases.

In order to study the texture evolution and magnetostriction behavior in the rolled Fe–Ga–B sheets during the heat treatments from low to high temperatures, (Fe 81 Ga 19 ) 98 B 2 sheets were prepared and investigated. The phase structure, recrystallization, grain size, texture evolution, and magnetostriction behavior during the annealing from 525 to 1200 °C for 1–5 h were investigated using X-ray diffraction, electron backscattering diffraction, and standard strain-gauge measurements. Results indicated that the primary recrystallization temperature for 1-h annealing was found as 525–575 °C in (Fe 81 Ga 19 ) 98 B 2 sheets. Annealing the sample below 575 °C for 1 h, the release of rolling stress and increase of 〈100〉 η -fiber texture during the primary recrystallization jointly resulted in a rapid improvement in magnetostriction. After annealed between 575 and 1100 °C for 1 h, the grains of the sheets underwent a normal growth, and the three ( α -, γ - and η -fiber) types of textures kept an approximate balance, leading to a plateau of magnetostriction around 75 ppm. When the abnormal grain growth proceeded above 1100 °C for 1 h, the proportion of η -fiber texture markedly increased, and the magnetostriction was subsequently increased to 97 ppm. For longer annealing durations, the strong ideal cube texture ( η -fiber) was firstly formed and then changed to undesired texture ( γ -fiber), producing a corresponding magnetostriction peak of 136 ppm at 2 h for the annealing at 1200 °C. The clear correlation among heat treatments, recrystallization, texture, and magnetostriction provides an essential understanding for Fe–Ga–B alloy sheets.