Transition Metal Dichalcogenides: Making Atomic-Level Magnetism Tunable with Light at Room Temperature.

The capacity to manipulate magnetization in 2D dilute magnetic semiconductors (2D-DMSs) using light, specifically in magnetically doped transition metal dichalcogenide (TMD) monolayers (M-doped TX , where M = V, Fe, and Cr; T = W, Mo; X = S, Se, and Te), may lead to innovative applications in spintronics, spin-caloritronics, valleytronics, and quantum computation. This Perspective paper explores the mediation of magnetization by light under ambient conditions in 2D-TMD DMSs and heterostructures. By combining magneto-LC resonance (MLCR) experiments with density functional theory (DFT) calculations, we show that the magnetization can be enhanced using light in V-doped TMD monolayers (e.

Large magnetoelectric resistance in the topological Dirac semimetal α-Sn.

The spin-momentum locking of surface states in topological materials can produce a resistance that scales linearly with magnetic and electric fields. Such a bilinear magnetoelectric resistance (BMER) effect offers a new approach for information reading and field sensing applications, but the effects demonstrated so far are too weak or for low temperatures. This article reports the first observation of BMER effects in topological Dirac semimetals; the BMER responses were measured at room temperature and were substantially stronger than those reported previously.

Iron Oxide Nanorings and Nanotubes for Magnetic Hyperthermia: The Problem of Intraparticle Interactions.

Magnetic interactions can play an important role in the heating efficiency of magnetic nanoparticles. Although most of the time interparticle magnetic interactions are a dominant source, in specific cases such as multigranular nanostructures intraparticle interactions are also relevant and their effect is significant. In this work, we have prepared two different multigranular magnetic nanostructures of iron oxide, nanorings (NRs) and nanotubes (NTs), with a similar thickness but different lengths (55 nm for NRs and 470 nm for NTs).

Switching of a Magnet by Spin-Orbit Torque from a Topological Dirac Semimetal.

Recent experiments show that topological surface states (TSS) in topological insulators (TI) can be exploited to manipulate magnetic ordering in ferromagnets. In principle, TSS should also exist for other topological materials, but it remains unexplored as to whether such states can also be utilized to manipulate ferromagnets. Herein, current-induced magnetization switching enabled by TSS in a non-TI topological material, namely, a topological Dirac semimetal α-Sn, is reported.

Monolayer Vanadium-Doped Tungsten Disulfide: A Room-Temperature Dilute Magnetic Semiconductor.

Dilute magnetic semiconductors (DMS), achieved through substitutional doping of spin-polarized transition metals into semiconducting systems, enable experimental modulation of spin dynamics in ways that hold great promise for novel magneto-electric or magneto-optical devices, especially for two-dimensional (2D) systems such as transition metal dichalcogenides that accentuate interactions and activate valley degrees of freedom. Practical applications of 2D magnetism will likely require room-temperature operation, air stability, and (for magnetic semiconductors) the ability to achieve optimal doping levels without dopant aggregation. Here, room-temperature ferromagnetic order obtained in semiconducting vanadium-doped tungsten disulfide monolayers produced by a reliable single-step film sulfidation method across an exceptionally wide range of vanadium concentrations, up to 12 at% with minimal dopant aggregation, is described.

Tunable Ferromagnetism and Thermally Induced Spin Flip in Vanadium-Doped Tungsten Diselenide Monolayers at Room Temperature.

The outstanding optoelectronic and valleytronic properties of transition metal dichalcogenides (TMDs) have triggered intense research efforts by the scientific community. An alternative to induce long-range ferromagnetism (FM) in TMDs is by introducing magnetic dopants to form a dilute magnetic semiconductor. Enhancing ferromagnetism in these semiconductors not only represents a key step toward modern TMD-based spintronics, but also enables exploration of new and exciting dimensionality-driven magnetic phenomena.

A magnetic sensor using a 2D van der Waals ferromagnetic material.

Two-dimensional (2D) van der Waals ferromagnetic materials are emerging as promising candidates for applications in ultra-compact spintronic nanodevices, nanosensors, and information storage. Our recent discovery of the strong room temperature ferromagnetism in single layers of VSe grown on graphite or MoS substrate has opened new opportunities to explore these ultrathin magnets for such applications. In this paper, we present a new type of magnetic sensor that utilizes the single layer VSe film as a highly sensitive magnetic core.

Strong room-temperature ferromagnetism in VSe monolayers on van der Waals substrates.

Reduced dimensionality and interlayer coupling in van der Waals materials gives rise to fundamentally different electronic , optical and many-body quantum properties in monolayers compared with the bulk. This layer-dependence permits the discovery of novel material properties in the monolayer regime. Ferromagnetic order in two-dimensional materials is a coveted property that would allow fundamental studies of spin behaviour in low dimensions and enable new spintronics applications.

Roles of bulk and surface magnetic anisotropy on the longitudinal spin Seebeck effect of Pt/YIG.

A clear understanding of the temperature evolution of the longitudinal spin Seebeck effect (LSSE) in the classic Pt/yttrium iron garnet (YIG) system and its association with magnetic anisotropy is essential towards optimization of its spin-caloric functionality for spintronics applications. We report here for the first time the temperature dependences of LSSE voltage (V ), magnetocrystalline anisotropy field (H ) and surface perpendicular magnetic anisotropy field (H ) in the same Pt/YIG system. We show that on lowering temperature, the sharp drop in V and the sudden increases in H and H at ~175 K are associated with the spin reorientation due to single ion anisotropy of Fe ions.

Epitaxial magnetite nanorods with enhanced room temperature magnetic anisotropy.

Nanostructured magnetic materials with well-defined magnetic anisotropy are very promising as building blocks in spintronic devices that operate at room temperature. Here we demonstrate the epitaxial growth of highly oriented FeO nanorods on a SrTiO substrate by hydrothermal synthesis without the use of a seed layer. The epitaxial nanorods showed biaxial magnetic anisotropy with an order of magnitude difference between the anisotropy field values of the easy and hard axes.

Angle resolved photoemission spectroscopy reveals spin charge separation in metallic MoSe grain boundary.

Material line defects are one-dimensional structures but the search and proof of electron behaviour consistent with the reduced dimension of such defects has been so far unsuccessful. Here we show using angle resolved photoemission spectroscopy that twin-grain boundaries in the layered semiconductor MoSe exhibit parabolic metallic bands. The one-dimensional nature is evident from a charge density wave transition, whose periodicity is given by k/π, consistent with scanning tunnelling microscopy and angle resolved photoemission measurements.