Showing papers on "Magnetization published in 2014"
TL;DR: In this article, it was shown that charge current flowing in-plane in a thin film of the topological insulator bismuth selenide (Bi2Se3) at room temperature can indeed exert a strong spin-transfer torque on an adjacent ferromagnetic permalloy (Ni81Fe19) thin film, with a direction consistent with that expected from the topologically surface state.
Abstract: Magnetic devices are a leading contender for the implementation of memory and logic technologies that are non-volatile, that can scale to high density and high speed, and that do not wear out. However, widespread application of magnetic memory and logic devices will require the development of efficient mechanisms for reorienting their magnetization using the least possible current and power. There has been considerable recent progress in this effort; in particular, it has been discovered that spin-orbit interactions in heavy-metal/ferromagnet bilayers can produce strong current-driven torques on the magnetic layer, via the spin Hall effect in the heavy metal or the Rashba-Edelstein effect in the ferromagnet. In the search for materials to provide even more efficient spin-orbit-induced torques, some proposals have suggested topological insulators, which possess a surface state in which the effects of spin-orbit coupling are maximal in the sense that an electron's spin orientation is fixed relative to its propagation direction. Here we report experiments showing that charge current flowing in-plane in a thin film of the topological insulator bismuth selenide (Bi2Se3) at room temperature can indeed exert a strong spin-transfer torque on an adjacent ferromagnetic permalloy (Ni81Fe19) thin film, with a direction consistent with that expected from the topological surface state. We find that the strength of the torque per unit charge current density in Bi2Se3 is greater than for any source of spin-transfer torque measured so far, even for non-ideal topological insulator films in which the surface states coexist with bulk conduction. Our data suggest that topological insulators could enable very efficient electrical manipulation of magnetic materials at room temperature, for memory and logic applications.
1,061 citations
TL;DR: This work reports the switching of out-of-plane magnetized Ta/Co(20)Fe(60)B(20)/TaO(x) structures by spin-orbit torques driven by in-plane currents, without the need for any external magnetic fields.
Abstract: Magnetization switching by current-induced spin-orbit torques is of great interest due to its potential applications in ultralow-power memory and logic devices. The switching of ferromagnets with perpendicular magnetization is of particular technological relevance. However, in such materials, the presence of an in-plane external magnetic field is typically required to assist spin-orbit torque-driven switching and this is an obstacle for practical applications. Here, we report the switching of out-of-plane magnetized Ta/Co(20)Fe(60)B(20)/TaO(x) structures by spin-orbit torques driven by in-plane currents, without the need for any external magnetic fields. This is achieved by introducing a lateral structural asymmetry into our devices, which gives rise to a new field-like spin-orbit torque when in-plane current flows in these structures. The direction of the current-induced effective field corresponding to this field-like spin-orbit torque is out-of-plane, facilitating the switching of perpendicular magnets.
789 citations
TL;DR: In this article, a review compiles results of experimental and theoretical studies on thin films and quantum structures of semiconductors with randomly distributed Mn ions, which exhibit spintronic functionalities associated with collective ferromagnetic spin ordering.
Abstract: This review compiles results of experimental and theoretical studies on thin films and quantum structures of semiconductors with randomly distributed Mn ions, which exhibit spintronic functionalities associated with collective ferromagnetic spin ordering. Properties of p-type Mn-containing III-V as well as II-VI, IV-VI, V-2 -VI3, I-II-V, and elemental group IV semiconductors are described, paying particular attention to the most thoroughly investigated system (Ga, Mn)As that supports the hole-mediated ferromagnetic order up to 190 K for the net concentration of Mn spins below 10%. Multilayer structures showing efficient spin injection and spin-related magnetotransport properties as well as enabling magnetization manipulation by strain, light, electric fields, and spin currents are presented together with their impact on metal spintronics. The challenging interplay between magnetic and electronic properties in topologically trivial and nontrivial systems is described, emphasizing the entangled roles of disorder and correlation at the carrier localization boundary. Finally, the case of dilute magnetic insulators is considered, such as (Ga, Mn)N, where low-temperature spin ordering is driven by short-ranged superexchange that is ferromagnetic for certain charge states of magnetic impurities.
731 citations
TL;DR: In this article, a magnetically doped topological insulator bilayer is shown to display a range of appealing characteristics for current-induced magnetization switching, including a significantly enhanced efficiency.
Abstract: Heterostructures consisting of ferromagnets and heavy metals have become a focus of interest because their strong spin–orbit coupling allows for efficient current-induced magnetization switching phenomena. Now, a magnetically doped topological insulator bilayer is shown to display a range of appealing characteristics for current-induced magnetization switching, including a significantly enhanced efficiency.
703 citations
TL;DR: The kinetics of the switching process is examined, something not considered previously in theoretical work, and a deterministic reversal of the DM vector and canted moment using an electric field at room temperature is shown.
Abstract: The technological appeal of multiferroics is the ability to control magnetism with electric field1, 2, 3. For devices to be useful, such control must be achieved at room temperature. The only single-phase multiferroic material exhibiting unambiguous magnetoelectric coupling at room temperature is BiFeO3 (refs 4 and 5). Its weak ferromagnetism arises from the canting of the antiferromagnetically aligned spins by the Dzyaloshinskii–Moriya (DM) interaction6, 7, 8, 9. Prior theory considered the symmetry of the thermodynamic ground state and concluded that direct 180-degree switching of the DM vector by the ferroelectric polarization was forbidden10, 11. Instead, we examined the kinetics of the switching process, something not considered previously in theoretical work10, 11, 12. Here we show a deterministic reversal of the DM vector and canted moment using an electric field at room temperature. First-principles calculations reveal that the switching kinetics favours a two-step switching process. In each step the DM vector and polarization are coupled and 180-degree deterministic switching of magnetization hence becomes possible, in agreement with experimental observation. We exploit this switching to demonstrate energy-efficient control of a spin-valve device at room temperature. The energy per unit area required is approximately an order of magnitude less than that needed for spin-transfer torque switching13, 14. Given that the DM interaction is fundamental to single-phase multiferroics and magnetoelectrics3, 9, our results suggest ways to engineer magnetoelectric switching and tailor technologically pertinent functionality for nanometre-scale, low-energy-consumption, non-volatile magnetoelectronics.
591 citations
TL;DR: It is demonstrated that all-optical helicity-dependent switching (AO-HDS) can be observed not only in selected rare earth-transition metal alloy films but also in a much broader variety of materials, including RE-TM alloys, multilayers and heterostructures.
Abstract: A promising strategy for achieving information storage devices with low energy consumption is to avoid using applied magnetic fields as a means to manipulate the magnetization of materials. Now, the class of materials that can be switched by all-optical means is shown to extend beyond alloys consisting of rare earths and transition metals.
531 citations
TL;DR: In this paper, the authors demonstrate deterministic magnetization reversal by current pulses ranging from 180 to ms in Pt/Co/AlOx dots with lateral dimensions of 90 nm, and characterize the switching probability and critical current Ic as a function of pulse length, amplitude, and external field.
Abstract: Spin-orbit torques induced by spin Hall and interfacial effects in heavy metal/ferromagnetic bilayers allow for a switching geometry based on in-plane current injection. Using this geometry, we demonstrate deterministic magnetization reversal by current pulses ranging from 180 ps to ms in Pt/Co/AlOx dots with lateral dimensions of 90 nm. We characterize the switching probability and critical current Ic as a function of pulse length, amplitude, and external field. Our data evidence two distinct regimes: a short-time intrinsic regime, where Ic scales linearly with the inverse of the pulse length, and a long-time thermally assisted regime, where Ic varies weakly. Both regimes are consistent with magnetization reversal proceeding by nucleation and fast propagation of domains. We find that Ic is a factor 3–4 smaller compared to a single domain model and that the incubation time is negligibly small, which is a hallmark feature of spin-orbit torques.
454 citations
TL;DR: In this article, a small electric field is used to switch a FeRh thin film from anti-to ferromagnetic above room temperature, by taking advantage of the strong magnetoelectric coupling with a BaTiO3 substrate.
Abstract: Electric-field-induced switching of material’s magnetization is a promising approach for achieving energy-efficient memory devices. By taking advantage of the strong magnetoelectric coupling with a BaTiO3 substrate, a small electric field is used to switch a FeRh thin film from anti- to ferromagnetic above room temperature.
443 citations
TL;DR: It is shown that a charge current produces a net spin polarization via spin-momentum locking in Bi2Se3 films, and this polarization is directly manifested as a voltage on a ferromagnetic contact.
Abstract: Topological insulators exhibit metallic surface states populated by massless Dirac fermions with spin-momentum locking, where the carrier spin lies in-plane, locked at right angles to the carrier momentum. Here, we show that a charge current produces a net spin polarization via spin-momentum locking in Bi2Se3 films, and this polarization is directly manifested as a voltage on a ferromagnetic contact. This voltage is proportional to the projection of the spin polarization onto the contact magnetization, is determined by the direction and magnitude of the charge current, scales inversely with Bi2Se3 film thickness, and its sign is that expected from spin-momentum locking rather than Rashba effects. Similar data are obtained for two different ferromagnetic contacts, demonstrating that these behaviours are independent of the details of the ferromagnetic contact. These results demonstrate direct electrical access to the topological insulators’ surface-state spin system and enable utilization of its remarkable properties for future technological applications. The spin-momentum locking in a topological insulator can be detected directly through electrical measurements.
417 citations
TL;DR: In this paper, the main features of structure and behavior of antiferromagnets, various microscopic and phenomenological models for description of the current-induced phenomena in heterostructures containing ferro-and antifromagnetic layers are considered.
Abstract: Spintronics of antiferromagnets is a new and rapidly developing field of the physics of magnetism. Even without macroscopic magnetization, antiferromagnets, similar to ferromagnetic materials are affected by spin-polarized current, and as in ferromagnets this phenomenon is based on a spin-dependent interaction between localized and free electrons. However, due to the nature of antiferromagnetic materials (complex magnetic structure, essential role of exchange interactions, absence of macroscopic magnetization) the study of possible spintronic effects requires new theoretical and experimental approaches. The purpose of this review is to systemize and describe recent developments in this area. After presenting the main features of structure and behavior of antiferromagnets various microscopic and phenomenological models for description of the current-induced phenomena in heterostructures containing ferro- and antiferromagnetic layers are considered. The questions related to an effect of antiferromagnetic ordering on an electric current, as well as the questions of possible creation of fully antiferromagnetic spin valves are discussed. In addition, we briefly discuss available experimental results and try to interpret them.
363 citations
TL;DR: This work shows that mononuclear complexes, called single-ion magnets (SIM), can be as efficient as polynuclear SMMs, thus opening new perspectives for their applications.
Abstract: Remanence and coercivity are the basic character- istics of permanent magnets. They are also tightly correlated with the existence of long relaxation times of magnetization in a number of molecular complexes, called accordingly single- molecule magnets (SMMs). Up to now, hysteresis loops with large coercive fields have only been observed in polynuclear metal complexes and metal-radical SMMs. On the contrary, mononuclear complexes, called single-ion magnets (SIM), have shown hysteresis loops of butterfly/phonon bottleneck type, with negligible coercivity, and therefore with much shorter relaxation times of magnetization. A mononuclear Er III complex is presented with hysteresis loops having large coercive fields, achieving 7000 Oe at T = 1.8 K and field variation as slow as 1 h for the entire cycle. The coercivity persists up to about 5 K, while the hysteresis loops persist to 12 K. Our finding shows that SIMs can be as efficient as polynuclear SMMs, thus opening new perspectives for their applications.
TL;DR: In this article, the authors present a consistent method to separate thermoelectric and spin-orbit torque (SOT) measurements in ferromagnet/normal-metal bilayers, in which thermal gradient produced by Joule heating and SOT coexist and give rise to ac transverse signals with comparable symmetry and magnitude.
Abstract: We present harmonic transverse voltage measurements of current-induced thermoelectric and spin-orbit torque (SOT) effects in ferromagnet/normal-metal bilayers, in which thermal gradients produced by Joule heating and SOT coexist and give rise to ac transverse signals with comparable symmetry and magnitude. Based on the symmetry and field dependence of the transverse resistance, we develop a consistent method to separate thermoelectric and SOT measurements. By addressing first ferromagnet/light-metal bilayers with negligible spin-orbit coupling, we show that in-plane current injection induces a vertical thermal gradient whose sign and magnitude are determined by the resistivity difference and stacking order of the magnetic and nonmagnetic layers. We then study ferromagnet/heavy-metal bilayers with strong spin-orbit coupling, showing that second harmonic thermoelectric contributions to the transverse voltage may lead to a significant overestimation of the antidamping SOT. We find that thermoelectric effects are very strong in Ta(6 nm)/Co(2.5 nm) and negligible in Pt(6 nm)/Co(2.5 nm) bilayers. After including these effects in the analysis of the transverse voltage, we find that the antidamping SOTs in these bilayers, after normalization to the magnetization volume, are comparable to those found in thinner Co layers with perpendicular magnetization, whereas the fieldlike SOTs are about an order of magnitude smaller.
TL;DR: The enhanced surface area of the MPC, as well as its graphite-like structure, may contribute to the adsorption capacity of TC, which could be effectively separated by applying a magnetic field.
TL;DR: In this paper, the TMR effect was applied to a three-terminal perpendicular magnetic tunnel junction by spin-orbit torque and its readout using the tunnelling magnetoresistance (TMR) effect.
Abstract: We report on the current-induced magnetization switching of a three-terminal perpendicular magnetic tunnel junction by spin-orbit torque and its read-out using the tunnelling magnetoresistance (TMR) effect. The device is composed of a perpendicular Ta/FeCoB/MgO/FeCoB stack on top of a Ta current line. The magnetization of the bottom FeCoB layer can be switched reproducibly by the injection of current pulses with density 5 × 1011 A/m2 in the Ta layer in the presence of an in-plane bias magnetic field, leading to the full-scale change of the TMR signal. Our work demonstrates the proof of concept of a perpendicular spin-orbit torque magnetic memory cell.
TL;DR: A thermally assisted magnetoresistive random access memory device (TAS-MRAM) with reduced power for reading and writing was proposed in this article, where the storage and sense ferromagnetic layers include a non-magnetic material to reduce the magnetization of the respective layers.
Abstract: A thermally assisted magnetoresistive random access memory device (TAS-MRAM) with reduced power for reading and writing; the memory device comprising a tunnel barrier 14 sandwiched between a ferromagnetic sense layer 16 and a ferromagnetic storage layer 12. An antiferromagnetic pinning layer 30 is disposed adjacent to the ferromagnetic storage layer 12. The pinning layer 30 pins a magnetic moment of the storage layer until heating is applied. Either or both of the storage and sense ferromagnetic layers includes a non-magnetic material to reduce the magnetization of the respective layers. The reduction in the storage layer magnetization and sense layer magnetization reduces the magnetostatic interaction between the storage layer and sense layer, resulting in less read/write power. The ferromagnetic materials in the sense and storage layers may include at least one of Co, Fe, Ni, and any alloy including Co, Fe, Ni, whilst the non-magnetic material includes at least one of Ta, Ti, Hf, Cr, Nb, Mo, Zr and any alloy containing Ta, Ti, Hf, Cr, Nb, Mo, Zr. The antiferromagnetic pinning layer may have a diameter less than 250nm based on the reduction in magnetization of at least one of the storage or sense layer. The ferromagnetic storage layer may be formed by sputtering ,chemical vapour (vapor) deposition CVD or physical vapour deposition PVD , and may involve co-sputtering the ferromagnetic and non magnetic material, or forming multi-layers of ferromagnetic and non magnetic material. The ferromagnetic sense layer may also be formed by co-sputtering of ferromagnetic and non magnetic material or forming multilayers of the two materials. An alternative embodiment (figures 7A/B) comprises a tunnel barrier layer 14 sandwiched between a ferromagnetic storage layer 16 and a synthetic antiferromagnetic storage layer 12, which includes a first ferromagnetic storage layer 11 adjacent to the tunnel barrier layer and a non magnetic coupling layer 15 sandwiched between the first ferromagnetic storage layer 11 and a second ferromagnetic storage layer 13. The alternative structure further allows for a relative increase in the thickness of the first ferromagnetic layer 11.
TL;DR: In this paper, the authors derived pumped spin and staggered spin currents in terms of the staggered field, the magnetization, and their rates of change, and connected the pumped currents to current-induced torques via Onsager reciprocity relations.
Abstract: Spin pumping and spin-transfer torques are two reciprocal phenomena widely studied in ferromagnetic materials. However, pumping from antiferromagnets and its relation to current-induced torques have not been explored. By calculating how electrons scatter off a normal metal-antiferromagnetic interface, we derive pumped spin and staggered spin currents in terms of the staggered field, the magnetization, and their rates of change. For both compensated and uncompensated interfaces, spin pumping is of a similar magnitude as in ferromagnets with a direction controlled by the polarization of the driving microwave. The pumped currents are connected to current-induced torques via Onsager reciprocity relations.
TL;DR: Nine typical SMTs are summarized, showing that the assembly of wheel-shaped complexes with the high symmetry of the molecule unit and strong intra-molecular dipolar interactions using strong anisotropy metal ions represents the most promising route toward the design of a toroidal moment.
Abstract: Single-molecule toroics (SMTs) are defined, by analogy with single-molecule magnets, as bistable molecules with a toroidal magnetic state, and seem to be most promising for future applications in quantum computing and information storage and use as multiferroic materials with magnetoelectric effect. As an interdisciplinary research area that spans chemistry, physics and material sciences, synthetic chemists have produced systems suitable for detailed study by physicists and materials scientists, while ab initio calculations have been playing a major role in the detection of toroidal magnetization and the advancement of this field. In this tutorial review, we demonstrate the research developed in the fascinating and challenging field of molecular-based SMTs with particular focus on how recent studies tend to address the issue of toroidal arrangement of the magnetic moment in these systems. Herein, nine typical SMTs are summarized, showing that the assembly of wheel-shaped complexes with the high symmetry of the molecule unit and strong intra-molecular dipolar interactions using strong anisotropy metal ions represents the most promising route toward the design of a toroidal moment. Furthermore, the linkage of such robust toroidal moment units with ferromagnetic type through appropriate bridging ligands enhances the toroidal magnetic moment per unit cell.
TL;DR: A study of the magnetic response of cobalt atoms adsorbed on oxide surfaces may lead to much denser storage of data, and the maximum magnetic anisotropy allowed for a transition metal atom is realized by coordinating a single Co atom to the O site of an MgO(100) surface.
Abstract: Designing systems with large magnetic anisotropy is critical to realize nanoscopic magnets. Thus far, the magnetic anisotropy energy per atom in single-molecule magnets and ferromagnetic films remains typically one to two orders of magnitude below the theoretical limit imposed by the atomic spin-orbit interaction. We realized the maximum magnetic anisotropy for a 3d transition metal atom by coordinating a single Co atom to the O site of an MgO(100) surface. Scanning tunneling spectroscopy reveals a record-high zero-field splitting of 58 millielectron volts as well as slow relaxation of the Co atom's magnetization. This striking behavior originates from the dominating axial ligand field at the O adsorption site, which leads to out-of-plane uniaxial anisotropy while preserving the gas-phase orbital moment of Co, as observed with x-ray magnetic circular dichroism.
TL;DR: In this paper, the authors discuss the properties of electromagnetic fields in heavy-ion collisions and consequences for observables, including quantitatively the issue of the magnetic field lifetime in a collision including the electric and chiral magnetic conductivities.
TL;DR: It is demonstrated that magnetic properties of ultrathin Co films adjacent to Gd2O3 gate oxides can be directly manipulated by voltage, opening a new route to achieve ultralow energy magnetization manipulation in spintronic devices.
Abstract: We demonstrate that magnetic properties of ultrathin Co films adjacent to Gd2O3 gate oxides can be directly manipulated by voltage. The Co films can be reversibly changed from an optimally oxidized state with a strong perpendicular magnetic anisotropy to a metallic state with an in-plane magnetic anisotropy or to an oxidized state with nearly zero magnetization, depending on the polarity and time duration of the applied electric fields. Consequently, an unprecedentedly large change of magnetic anisotropy energy up to 0.73 erg/cm(2) has been realized in a nonvolatile manner using gate voltages of only a few volts. These results open a new route to achieve ultralow energy magnetization manipulation in spintronic devices.
TL;DR: In this paper, temperature dependent structural, magnetic and optical properties of NiFe2O4 nanoparticles have been investigated using X-ray diffraction patterns and Raman spectroscopy.
TL;DR: Compared to the only reliable quantitative (13)C NMR method for unlabeled solids previously available, namely direct-polarization NMR, the measuring time is reduced by more than a factor of 50, enabling higher-throughput quantitative NMR studies.
TL;DR: In this article, the magnetic properties of hematite nanoparticles were investigated using a superconducting quantum interference device (SQUID) magnetometry, which showed a divergence between field-cooled (FC) and zero-field cooled (ZFC) magnetization curves below Tirr = 103 K (irreversibility temperature) and the ZFC magnetization curve showed maximum at TB = 52 K (blocking temperature).
IBM1
TL;DR: This work shows that this torque is manifested when the magnetic layer is interfaced with metals that display a large proximity-induced magnetization, including iridium, palladium and platinum but not gold, and shows that high domain velocities are found where there are large proximity -induced magnetizations in the interfaced metal layers.
Abstract: Domain walls can be driven at high speeds in perpendicularly magnetized nanowires grown on heavy metal underlayers due to a chiral spin torque. Here, the authors show that this torque is related to the proximity-induced magnetization in the underlayer and can be tuned through interface engineering.
TL;DR: In this paper, an integral integral over the quark masses up to asymptotically large values where the effect of the magnetic field can be neglected is used to determine the free energy at nonzero magnetic fields.
Abstract: We determine the equation of state of 2+1-flavor QCD with physical quark masses, in the presence of a constant (electro)magnetic background field on the lattice. To determine the free energy at nonzero magnetic fields we develop a new method, which is based on an integral over the quark masses up to asymptotically large values where the effect of the magnetic field can be neglected. The method is compared to other approaches in the literature and found to be advantageous for the determination of the equation of state up to large magnetic fields. Thermodynamic observables including the longitudinal and transverse pressure, magnetization, energy density, entropy density and interaction measure are presented for a wide range of temperatures and magnetic fields, and provided in ancillary files. The behavior of these observables confirms our previous result that the transition temperature is reduced by the magnetic field. We calculate the magnetic susceptibility and permeability, verifying that the thermal QCD medium is paramagnetic around and above the transition temperature, while we also find evidence for weak diamagnetism at low temperatures.
TL;DR: This work studies the magnetic properties of Bi2Se3 surface states in the proximity of a high Tc ferrimagnetic insulator, yttrium iron garnet (YIG or Y3Fe5O12), and demonstrates the proximity-induced TI magnetism at higher temperatures.
Abstract: Introducing magnetic order in a topological insulator (TI) breaks time-reversal symmetry of the surface states and can thus yield a variety of interesting physics and promises for novel spintronic devices To date, however, magnetic effects in TIs have been demonstrated only at temperatures far below those needed for practical applications In this work, we study the magnetic properties of Bi2Se3 surface states (SS) in the proximity of a high Tc ferrimagnetic insulator (FMI), yttrium iron garnet (YIG or Y3Fe5O12) Proximity-induced butterfly and square-shaped magnetoresistance loops are observed by magneto-transport measurements with out-of-plane and in-plane fields, respectively, and can be correlated with the magnetization of the YIG substrate More importantly, a magnetic signal from the Bi2Se3 up to 130 K is clearly observed by magneto-optical Kerr effect measurements Our results demonstrate the proximity-induced TI magnetism at higher temperatures, an important step toward room-temperature applicati
TL;DR: In this article, a superparamagnetic ZnFe2O4/reduced graphene oxide (rGO) composite was synthesized by a hydrothermal reaction method and the time needed for 90% separation from its solution was found 60min in the presence of an external magnetic field (∼1−Tesla).
TL;DR: Pseudooctahedral mononuclear cobat(II) complex, where abpt = 4-amino-3,5-bis(2-pyridyl)-1,2,4-triazole and tcm = tricyanomethanide anion, shows field-induced slow relaxation of magnetization, presenting a new example of a field- induced single-ion magnet with transversal magnetic anisotropy.
Abstract: Pseudooctahedral mononuclear cobat(II) complex [Co(abpt)2(tcm)2] (1), where abpt = 4-amino-3,5-bis(2-pyridyl)-1,2,4-triazole and tcm = tricyanomethanide anion, shows field-induced slow relaxation of magnetization with U = 86.2 K and large axial and rhombic single-ion zero-field-splitting parameters, D = +48(2) cm–1 and E/D = 0.27(2) (D = +53.7 cm–1 and E/D = 0.29 from ab initio CASSCF/NEVPT2 calculations), thus presenting a new example of a field-induced single-ion magnet with transversal magnetic anisotropy.
TL;DR: In this article, the influences of strain on electronic structure and magnetic properties of commonly observed vacancies doped monolayer MoS2 systems were investigated using first-principles calculations.
Abstract: In view of important role of inducing and manipulating the magnetism in two-dimensional materials for the development of low-dimensional spintronic devices, the influences of strain on electronic structure and magnetic properties of commonly observed vacancies doped monolayer MoS2 are investigated using first-principles calculations. It is shown that unstrained VS, VS2, and VMoS3 doped monolayer MoS2 systems are nonmagnetic, while the ground state of unstrained VMoS6 doped system is magnetic and the magnetic moment is contributed mainly by six Mo atoms around VMoS6. In particular, tensile strain can induce magnetic moments in VS, VS2, and VMoS3 doped monolayer MoS2 due to the breaking of Mo–Mo metallic bonds around the vacancies, while the magnetization induced by VMoS6 can be effectively manipulated by equibiaxial strain due to the change of Mo–Mo metallic bonds around VMoS6 under strains.
TL;DR: The nucleation of reversed magnetic domains in Pt/Co/AlO(x) microstructures with perpendicular anisotropy was studied experimentally in the presence of an in-plane magnetic field and it was observed to depend in a chiral way on the initial magnetization and applied field directions.
Abstract: The nucleation of reversed magnetic domains in Pt/Co/AlO(x) microstructures with perpendicular anisotropy was studied experimentally in the presence of an in-plane magnetic field. For large enough in-plane field, nucleation was observed preferentially at an edge of the sample normal to this field. The position at which nucleation takes place was observed to depend in a chiral way on the initial magnetization and applied field directions. A quantitative explanation of these results is proposed, based on the existence of a sizable Dzyaloshinskii-Moriya interaction in this sample. Another consequence of this interaction is that the energy of domain walls can become negative for in-plane fields smaller than the effective anisotropy field.