Explore the vast range of titles available.

The discovery of van der Waals magnets has established a new domain in the field of magnetism, opening novel pathways for the electrical control of magnetic properties. In this context, Fe3GeTe2 (FGT) emerges as an exemplary candidate owing to its intrinsic metallic properties, which facilitate the interplay of both charge and spin degrees of freedom. Here, the bidirectional voltage control of exchange bias (EB) effect in a perpendicularly magnetized all‐van der Waals FGT/O‐FGT/hBN heterostructure is demonstrated. The antiferromagnetic O‐FGT layer is formed by naturally oxidizing the FGT surface. The observed EB magnitude reaches 1.4 kOe with a blocking temperature (150 K) reaching close to the Curie temperature of FGT. Both the exchange field and the blocking temperature values are among the highest in the context of layered materials. The EB modulation exhibits a linear dependence on the gate voltage and its polarity, observable in both positive and negative field cooling (FC) experiments. Additionally, gate voltage‐controlled magnetization switching, highlighting the potential of FGT‐based heterostructures is demonstrated in advanced spintronic devices. These findings display a methodology to modulate the magnetism of van der Waals magnets offering new avenues for the development of high‐performance magnetic devices. Their research explores van der Waals magnets and uses a perpendicularly magnetized FGT/O‐FGT/hBN heterostructure to demonstrate gate voltage‐controlled magnetization switching. They observe bidirectional voltage control of exchange bias (EB), with the highest EB magnitude of 1.4 kOe and a blocking temperature of 150 K, both among the highest for layered materials.

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.

The 2H-phase of monolayer vanadium diselenide (VSe ) has recently emerged as a very intriguing material in spintronics due to its intrinsic ferromagnetism with semiconducting properties. In the present work, first-principles based calculations have been employed to systematically study the electronic, magnetic, and optical behaviour of 2D VSe for investigating the impact of different external excitations such as strain, electric field, and pressure on the material. Specifically, the magnetic moment, band gap, Curie temperature (T ), and absorption coefficient could be modulated, as the states near the Fermi level are mainly contributed by the in-plane atomic orbitals. The presence of different electronic phases in 2D VSe can be modulated from semiconductor to half-metal and even normal metal under the influence of external stimuli. Furthermore, the in-plane biaxial strain can effectively tune the T and attains a maximum value of 354K at = 6%. The maximum observed absorption coefficient is found to be 5.05 10 cm (at 1.4 eV) under the applied pressure of 30 GPa, indicating that the VSe exhibits strong light absorption in the visible region. The unique combination of electronic phases, robust ferromagnetism, and optical activity makes the 2H-VSe a suitable candidate for flexible electronic, optoelectronic, and spintronic applications.

Compared to other 2D materials, MBenes are at an early stage of investigation in terms of both experimental and theoretical approaches. However, their wide range of possible 2D structures leads to novel and challenging properties and consequent applications. From all the possible stoichiometries, we performed a theoretical study of orthorhombic and hexagonal M2B2 MBenes within the framework of density functional theory. We found that both symmetries of Cr2B2, Fe2B2, and Zr2B2 show metallic behavior and could be grown under certain conditions as they were demonstrated to be dynamically stable. Moreover, the values of the magnetic moment observed, in specific ferromagnetic cases exceeding 2.5μB/M2B2, make them suitable as robust 2D magnets. Our findings represent an important step in the understanding of MBenes and open several windows to future research in fields like energy conversion and storage, sensing, catalysis, biochemistry, and nanotechnology, among others.

In the post graphene era, the discovery of magnetism in two-dimensional (2D) intrinsic nanomagnets has opened up exciting possibilities for low-dimensional spintronics. In this article, we have reported three new 2D Janus nanomagnets VBrCl 2 , VBrI 2 , and VClBrI for the first time. First-principles based density functional theory calculations reveal that these monolayers are intrinsically magnetic with indirect band gap semiconducting properties and further the magnetic and electronic properties of these monolayers are enhanced with the application of biaxial strain and electric field. We observe interesting electronic and magnetic phase transitions, tunable band gap, and supreme enhancement of the Curie temperature (~ 686%). Large magnetic anisotropic energy (MAE) with high magnetic moment and tunable band gap property make these Janus materials useful candidates for future information storage, optoelectronics, and 2D spin circuit development. Graphical abstract

Traditional magnetic phase diagram represents a transition between the ferromagnetic and paramagnetic states of a material under the influence of varied temperature, magnetic field, and pressure. So far, the ferromagnetic phase has been considered predominantly as a single type of magnetization texture extending macroscopically in the bulk of a crystal, existing as a ground state determined by the interactions between localized magnetic moments arranged in a lattice. Here, it is demonstrated that an unconventional magnetic order composed of vertically correlated planar magnetic sub‐domains occurs intrinsically in mechanically exfoliated layers of van der Waals ferromagnet CrBr3. Based on the visualization of the magnetic textures through magnetic force microscopy in conjunction with the ab initio calculations of the crystal structure in the magnetic phase and micromagnetic simulations, the origin of the magnetic sub‐domains is attributed to stacking faults isolating a van der Waals ferromagnetic well from the bulk film due to modifications in the interlayer exchange coupling. This enables to create a phase diagram describing the magnetic states unique to van der Waals ferromagnets in terms of the degree of correlation between the magnetic sub‐domains, dependent on the exchange coupling constants and tuneable by magnetic field and temperature. An unconventional magnetic order is observed in exfoliated CrBr3 layers, characterized by vertically correlated planar magnetic sub‐domains. Magnetic force microscopy, ab initio calculations, and micromagnetic simulations indicate that these sub‐domains arise from stacking faults modifying interlayer exchange coupling. A phase diagram is developed to describe unique magnetic states in van der Waals ferromagnets, tunable by magnetic field and temperature.

Covalent 2D magnets such as Cr2Te3, which feature self‐intercalated magnetic cations located between monolayers of transition‐metal dichalcogenide material, offer a unique platform for controlling magnetic order and spin texture, enabling new potential applications for spintronic devices. Here, it is demonstrated that the unconventional anomalous Hall effect (AHE) in Cr2Te3, characterized by additional humps and dips near the coercive field in AHE hysteresis, originates from an intrinsic mechanism dictated by the self‐intercalation. This mechanism is distinctly different from previously proposed mechanisms such as topological Hall effect, or two‐channel AHE arising from spatial inhomogeneities. Crucially, multiple Weyl‐like nodes emerge in the electronic band structure due to strong spin‐orbit coupling, whose positions relative to the Fermi level is sensitively modulated by the canting angles of the self‐intercalated Cr cations. These nodes contribute strongly to the Berry curvature and AHE conductivity. This component competes with the contribution from bands that are less affected by the self‐intercalation, resulting in a sign change in AHE with temperature and the emergence of additional humps and dips. The findings provide compelling evidence for the intrinsic origin of the unconventional AHE in Cr2Te3 and further establish self‐intercalation as a control knob for engineering AHE in complex magnets. The unconventional anomalous Hall effect (AHE) in Cr2Te3, characterized by a sign change and humps and dips near the coercive field in its hysteresis, is attributed to an intrinsic mechanism dictated by self‐intercalated Cr atoms with spin canting, closely linked to multiple band anti‐crossings near the Fermi level.

2D van der Waals (vdW) magnets with layer‐dependent magnetic states and/or diverse magnetic interactions and anisotropies have attracted extensive research interest. Despite the advances, a notable challenge persists in effectively manipulating the tunneling anisotropic magnetoresistance (TAMR) of 2D vdW magnet‐based magnetic tunnel junctions (MTJs). Here, this study reports the novel and anomalous tunneling magnetoresistance (TMR) oscillations and pioneering demonstration of bias and gate voltage controllable TAMR in 2D vdW MTJs, utilizing few‐layer CrPS4. This material, inherently an antiferromagnet, transitions to a canted magnetic order upon application of external magnetic fields. Through TMR measurements, this work unveils the novel layer‐dependent oscillations in the tunneling resistance for few‐layer CrPS4 devices under both out‐of‐plane and in‐plane magnetic fields, with a pronounced controllability via gate voltage. Intriguingly, this study demonstrates that both the polarity and magnitude of TAMR in CrPS4 can be effectively tuned through either a bias or gate voltage. The mechanism behind this electrically tunable TAMR is further elucidated through first‐principles calculations. The implications of the findings are far‐reaching, providing new insights into 2D magnetism and opening avenues for the development of innovative spintronic devices based on 2D vdW magnets. The report studies magnetic tunneling junctions based on 2D CrPS4. Anomalous tunneling magnetoresistance oscillations are found, which probably are signatures of spin geometric phase. Furthermore, this study demonstrates that both bias and gate voltages can manipulate the magnitude and polarity of tunneling anisotropic magnetoresistance in few‐layer CrPS4.

Phosphorene is a unique semiconducting two-dimensional platform for enabling spintronic devices integrated with phosphorene nanoelectronics. Here, we have designed an all phosphorene lattice lateral spin valve device, conceived via patterned magnetic substituted atoms of 3d-block elements at both ends of a phosphorene nanoribbon acting as ferromagnetic electrodes in the spin valve. Through First-principles based calculations, we have extensively studied the spin-dependent transport characteristics of the new spin valve structures. Systematic exploration of the magnetoresistance (MR) of the spin valve for various substitutional atoms and bias voltage resulted in a phase diagram offering a colossal MR for V and Cr-substitutional atoms. Such MR can be directly attributed to their specific electronic structure, which can be further tuned by a gate voltage, for electric field controlled spin valves. The spin-dependent transport characteristics here reveal new features such as negative conductance oscillation and switching of the sign of MR due to change in the majority spin carrier type. Our study creates possibilities for the design of nanometric spin valves, which could enable integration of memory and logic elements for all phosphorene 2D processors.

Two-dimensional materials provide with ability to control their properties with a number of methods. One of such methods is using strain and compression. In this work, we investigated the influence of locally induced strain through bubbles in thin ferromagnetic CrBr3 using low-temperature magnetic force microscopy. As a result, domain pinning and higher coercive and saturation fields were observed in the bubble. In addition, nontrivial spin arrangements are allowed to take place in a non-homogeneously strained area, leading to different responses to the external magnetic field in comparison to a non-strained region. Finally, Raman spectroscopy and magneto-photoluminescence spectroscopy were performed to show alternation of the magnetic properties of the sample under mechanical deformation.