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Ferroelectric polarizationhas been considered to be an key factor to tune the structural and photoelectric properties of perovskites and their heterostructures. While there has been growing researches made in the novel phenomena originating from interface formed between oxide perovskites, the effects of ferroelectric polarization on the electronic properties of halide perovskites and their heterostructures are rarely studied. Herein, by using first-principles calculations, all-inorganic halide perovskite heterostructure composed of 3D perovskite tetragonal CsPbBr3 and 2D Ruddlesden-Popper (RP) perovskite Cs2PbI2Cl2 is constructed for disclosing the relationship between the intrinsic polarization of tetragonal CsPbBr3 and electronic band structure of heterostructure. Cs atoms and Pb atoms of tetragonal CsPbBr3 in heterostructure are artificially moved away from the equivalent centers to simulate increased polarization. Our results show that with the spontaneous polarization of tetragonal CsPbBr3 increasing, the bandgap of heterostructure decreases, and the band alignment switches from staggered type-II to broken-gap type-III. Moreover, large cation-anion displacements along z-direction in tetragonal CsPbBr3 can be observed when tensile strains (≥5%) are applied, indicating a increased ferroelectric polarization, which also facilitates the decreasing of bandgap in heterostructure and the type-II-type-III transition of band alignment. Our study suggests that control over the polarization of ferroelectric materials is of great importance to tune the photoelectric properties of perovskite-based devices.

The structure stabilities, elastic properties, and electronic structures of L12-and D022-TiAl3 under different pressures have been investigated by the first-principles. The formation energy shows that both L12-TiAl3 and D022-TiAl3 were stable at pressure up to 40 GPa. There would be a phase transition from D022 phase to L12 phase when pressure is about 25 GPa D022-TiAl3 and L12-TiAl3 satisfy the mechanical property stability, and both the stiffness and plasticity increase with the increase of pressure. The elastic anisotropy of D022 structure is larger than the L12 structure. The bonding situation and electronic properties of TiAl3 (L12 and D022) were analyzed by differential charge density and density of states (DOS) curve.

Two-dimensional (2D) material-based van der Waals heterostructures (vdWHs) have been identified as an excellent platform from which to expand various device applications for light-emitting, photovoltaic, and field-effect transistors because of their different band alignments, including type-I, type-II, and type-III. However, it is difficult to achieve transformations between types of band alignment in a single heterostructure for diverse applications. In this study, the effects of a vertical electric field on the band alignment transition and electronic properties of 2D ${\rm{GaSe}}/{\rm{SnS}}_{2}$ (${\rm{SnSe}}_{2}$) vdWHs are investigated systematically using density functional theory calculations. The study shows that the electric field can modulate not only the band gap but also the band alignment to produce multifunctional device applications. A positive electric field can control the band alignment transformation from type-II to type-I for electric field values of approximately 0.39 V/\AA{} (0.12 V/\AA{}), while a negative electric field can transform the type-II to type-III band alignments for electric field values of about \ensuremath{-}0.2 V/\AA{} (\ensuremath{-}0.16 V/\AA{}) in ${\rm{GaSe}}/{\rm{SnS}}_{2}$ (${\rm{SnSe}}_{2}$) vdWHs. We trace these surprising results to the conduction band and valence band edge position movements for the linear decrease of ${\rm{GaSe}}$, while the linear increase of ${\rm{SnS}}_{2}$ (${\rm{SnSe}}_{2}$) occurs with the applied electric field. The present work may provide a direction for tunable multiple-band alignments in 2D vdWHs and help achieve multifunctional device applications.

We present a comparative study on the ferromagnetic and antiferromagnetic chiral domain walls under non-gradient spin torques by collective coordinates method. Based on the steady solutions, the stable chiral walls are picked out by linear stability analysis. We find that the spin torques drive the antiferromagnetic wall more quickly and stable than the ferromagnetic one. For the antiferromagnetic wall, the velocity is proportional to the exchange interaction, while Dzyaloshinskii-Moriya interaction for the ferromagnetic wall. Due to the strongness of exchange interaction, the antiferromagnetic wall propagates much faster than the ferromagnetic one. In addition, the antiferromagnetic wall remains the Neel type, while the ferromagnetic wall switches to a Bloch type with the current increasing. Finally, Dzyaloshinskii-Moriya interaction influences the motion direction of antiferromagnetic wall, but has no effect on the magnitude of velocity. For ferromagnetic walls, it determines the magnitude of velocity.

With the development of lightweight vehicles, aluminum alloy sheets are increasingly used in the automotive field. However, the aluminum alloy sheet has poor forming performance at room temperature. Therefore, how to improve the sheet metal forming performance of aluminum alloy sheet has become one of the current research hotspots. In this paper, the effects of different lubricants on the deep drawing forming properties of 6061 aluminum alloy sheets were studied by cupping experiments. The effects of lubricants on the deep drawing of sheet metal forming and the wall thickness of cups after deep drawing were explored. The results show that under the condition of drawing speed of 3MPa and 200mm/min, the ultimate drawing ratio of the sheet under oil lubrication is 1.92, and the PTFE film is 2.16. Grease and graphite lubrication are respectively 2.12 and 2.03, using PTFE film lubrication can increase by about 10% contrast with the oil lubrication. The measurement of the wall thickness of the cup under the forming limit state shows that the position with the largest reduction rate appears in the rounded transition zone, and the wall portion of the cylindrical member increases with the height of the wall, and the thickness from the bottom of the cup to the bottom of the cup. The edges all show a trend of decreasing first and then increasing.

In recent years, two-dimensional (2D) organic–inorganic perovskites have been attracting considerable attention because of their unique performance and enhanced stability for photovoltaic solar cells or photoluminescent devices. However, how the two-dimensionality affects the photoelectric properties of all-inorganic perovskites remains unclear. In this work, the electronic and optical properties including band structures, carrier mobility, optical absorption spectra and exciton-binding energies for the all-inorganic perovskite Cs2PbI4 with a Ruddlesden–Popper (RP) structure are investigated systemically by using density functional theory with a spin orbit coupling (SOC) effect. The calculated results demonstrate the thickness-dependence of electronic properties in the all-inorganic 2D RP perovskite Cs2PbI4 and its carrier mobility which is comparable to that of CsPbI3 thin films. The exciton-binding energies of perovskite Cs2PbI4 with a RP structure increase with the decrease of the number of layers. Besides, the value of exciton-binding energy for monolayers (181.70 meV) is more than 3 times larger than that of CsPbI3 (59.12 meV). Moreover, the calculated results show that two dimensional layered Ruddlesden–Popper perovskite Cs2PbI4 may not be a good material for photovoltaic applications due to its low carrier mobility and poor visible light absorption, but may be a good material for light-emission applications due to its larger thickness-dependent exciton binding energy. Our work would provide a theoretical basis for other ultrathin two-dimensional perovskite materials with potential application for photoluminescent devices or solar absorbers.

We theoretically investigate the Dzyaloshinskii–Moriya solitons driven by the magnetic field and spin-polarized current in anisotropic ferromagnetic nanowires. The external field and Dzyaloshinskii–Moriya interaction determine the formation region of soliton solution and the corresponding phase diagram is given for different types of solitons. The Dzyaloshinskii–Moriya interaction affects the internal structure distortion of solitons which determines the soliton energy. Also, we obtain the critical value of Dzyaloshinskii–Moriya interaction for soliton formation. The roles of Dzyaloshinskii–Moriya interaction effect on the soliton energy are completely opposite for the solitons of type I and type II in ferromagnetic nanowires.

The dynamics of domain wall driven by the spin-orbit torques is theoretically studied in the heavy metal/ferromagnet bilayer with Dzyaloshinskii-Moriya interaction (DMI) and in-plane magnetic anisotropy. Based on the Walker profile, we infer that DMI has a selectivity for the chirality of head-to-head (tail-to-tail) static wall. By analyzing the dynamic equations obtained from the collective coordinates methods, we find that there exists a switching or a hysteresis of the polarity of wall in the low-current regime. In the presence of DMI, the wall can keep sustained propagation which velocity saturates for high current and is proportional to the strength of DMI. Furthermore, the DMI makes the adjacent walls possess the same chirality and move in the same direction.

We investigate the spin-related currents and tunnel magnetoresistance through a quantum dot, which is side-coupled with a Majorana fermion zero mode and two thermal-driven ferromagnetic electrodes. It is found that the interplay of Majorana fermion and electrodes’ spin polarization can induce a nonlinear thermal-bias spin current. This interplay also decreases the total magnitude of spin or charge current, in either parallel or antiparallel configuration. In addition, a thermal-driven negative tunnel magnetoresistance is found, which is an unique feature to characterize Majorana fermion. With large temperature difference, a step phenomenon is observed in gate tuned spin-up current. When the coupling between quantum dot and topological superconductor is strong enough, this step will evolve into a linear relation, revealing Majorana fermion’s robustness.

In quantum transport, especially in spintronics, its central theme is to manipulate spin degrees of freedom in solid-state systems, to understand the interaction between the particle spin and its solid-state environments and to make useful devices. Recently, Majorana fermion has been introduced into quantum transport and received much attention. In this paper, we study a thermal-driven transport model which consists of a quantum dot coupled with two normal metal leads, a impurity spin (whose angular quantum number is more than or equal to one-half) and a Majorana fermion. We focus on the interplay between Majorana fermion and the impurity in this exactly solvable model. It is found that the system can generate thermal-induced spin current, and the currents are affected by Majorana fermion and impurity. With large temperature difference, the currents are sensitive to gate voltage, and the quantitative relation between spin-up current and gate voltage tends to be linear when the coupling between Majorana and quantum dot is strong, showing Majorana fermion's robustness. In addition, the spin current induced by Majorana fermion exhibits an oscillating antisymmetric structure around zero-bias point. This spin current’s zero point is related to the angular quantum number of impurity spin. These results are expected to be useful in thermal-electric conversion devices, and may be observed in future experiments.

In this study, based on density functional theory, the formation enthalpy, density of states, elastic properties and elastic anisotropy of Al3M (M = Ti, Ta, V, Nb, Hf) compounds were calculated. The calculation results of enthalpy formation indicate that Al3M (M = Ti, Ta, V, Nb, Hf) compounds are formed. State density analysis of Al3M (M = Ti, Ta, V, Nb, Hf) compounds at the Fermi level is non-zero, showing metal properties. The density of states show that Al3Ta has the highest structural stability. The calculation results of mechanical properties show that Al3Ta has greater resistance to bulk deformation and shear deformation. By calculating the anisotropic indexes, the sequence of anisotropy in elastic modulus is Al3Hf > Al3Ti > Al3V > Al3Nb > Al3Ta.

We theoretically investigate the effect of Dzyaloshinskii-Moriya interaction (DMI) on magnetic solitons in anisotropic ferromagnetic wires driven by the adiabatic spin-transfer torque. The DMI changes the formation region of soliton solution and the corresponding phase diagram is given for different types of soliton solutions. Also, it affects the processional frequency and the internal structure distortion of solitons. We show that the DMI decreases the energy for symmetric soliton while increases the energy for antisymmetric one. It implies that the DMI favours the more steady state of magnetization for the case of strong easy-axis anisotropy.

Coordination polymers (CPs) have shown promising potential as electrode materials for lithium ion batteries (LIBs). However, their practical applications are plagued by poor cyclability and unsatisfactory rate performance. Herein, a composite, combining a novel Ce-Co bimetallic coordination polymer with cerium dioxide and graphene nanoplatelets (Ce-Co-CP/CeO2/G), is synthesized and applied as anode materials for LIBs. It is found that the addition of graphene can significantly enhance the conductivity of electrode material. Furthermore, the graphene nanoplatelets can act as a template for the formation of a lamellar morphology of Ce-Co-CP/CeO2/G, which is beneficial to shorten the pathway for Li+-ion migration and thus improves the electrochemical performance. Consequently, the charge capacity of the sample reaches 454.3 mAh/g after 100 cycles at a current of 100 mA/g. Even at a high current density of 1000 mA/g, it can still deliver a capacity of 196.2 mAh/g after 1000 cycles. This work shows a development potential of bimetallic CP materials as a candidate for electrode materials for the next-generation LIBs.

Based on the uniform, helical and spiral domain-wall magnetic configurations, the excited spin waves are studied with emphasis on the role of damping. We find that the damping closes the gap of dispersion, and greatly influences the dispersion in the long-wave region for the spin waves of spiral wall and helical structure. For the uniform configuration, the Dzyaloshinskii–Moriya interaction determines the modification of dispersion by the damping. Furthermore, we investigate the interaction between spin waves and a moving spiral domain wall. In the presence of damping, the amplitude of spin wave can increase after running across the wall for small wave numbers. Driving by the spin waves, the wall propagates towards the spin-wave source with an increasing velocity. Unlike the case without damping, the relation between the wall velocity and the spin-wave frequency depends on the position of wall.

There has been great interest inhow to boost the performance of perovskite solar cells effectively. Building heterostructures between layered two-dimensional materials and perovskites is a common way to achieve the goal. In this work, the electronic and optical properties of the MoS2/CsPbBr3 heterostructure are studied systematically by density functional theory calculations. The calculated results show that the heterostructure can effectively retain some of the excellent properties of individual MoS2 and CsPbBr3. Furthermore, the optical performance of the two kinds of interfaces—CsBr/MoS2 contact and PbBr2/MoS2 contact—is better than that of the individual perovskite layers. We attribute the increased light absorption to the type II electronic band alignment of the heterostructure, interfacial charge transfer, and electron-hole separation. This work may be beneficial for improving the properties of perovskite solar cells and may open a way for the theoretical exploration of inorganic perovskite–based heterostructures.

Electroluminescence devices based all-inorganic halide perovskite material with the excellent luminescence performance have been studied extensively in recent years . However, the important role for the electrodes of electroluminescence devices is payed few attention by theoretical and experimental studies. Appropriate electrodes can reduce the Schottky barrier height to decrease the energy loss, and prevent the metal impurities from diffusing into the perovskite material to generate deep impurity levels, which improves the luminous efficiency and lifetime of devices. In this paper, not only the interface effects between CsPbBr3 and common metal electrode (Ag, Au, Ni, Cu and Pt) are studied by first-principle calculations, but also the diffusion effects of metal electrode atom into the CsPbBr3 layer are also explored by nudged elastic band calculations. The calculated results show the metal Ag is more suitable for the cathode for CsPbBr3 electroluminescence devices, while the metal Pt is more applicable for the anode. Based on the overall consideration about the interface effects and diffusion effects of the CsPbBr3-metal electrode junctions, the essential principle is analyzed. The work provides theoretical guidance for how to select the right electrode for the electroluminescence performance of all-inorganic halide perovskite. The critical factor of Schottky barrier height between the electrode and the light-emitting semiconductor, and transition level generated by metal impurities also provide a valuable reference how to select the suitable electrodes for other electroluminescence devices.

In terms of Darboux transformation we investigate the dynamic process of spin wave passing through a magnetic soliton. It causes nonlinear excitations, such as Akhmediev breathers solution and Kuznetsov-Ma soliton. The former case demonstrates a spatial periodic process of a magnetic soliton forming the petal with four pieces. The spatial separation of adjacent magnetic petals increases rapidly, while one valley splits into two and the amplitude of valley increases gradually with the increasing amplitude of spin wave. The other case shows a localized process of the spin-wave background. In the limit case, we get rogue waves and clarify its formation mechanism.

We study the transport through an isotropic single molecular magnet ( S =1) with electron–vibron coupling using Keldysh's non-equilibrium Green function based on Hubbard operator. Electron–vibron coupling smooths the current steps due to the broadening of effective channel levels and shifts the elastic resonance peaks in differential conductance down in energy. At low temperature vibron-assisted peaks appear only at energies above the elastic resonance due to the absence of vibron excitation. The electron–vibron coupling also leads to the increase of shot noise, which gets more evident with increasing electron–vibron coupling.

We have analytically studied the magnetization dynamics in magnetic trilayers with perpendicular anisotropy for both free and pinned layers. By linear stability analysis, we obtain the phase diagram parameterized by the current, magnetic field and relative strength of the field-like spin torque to Slonczewski torque. Under the control of the current and external magnetic field, several magnetic states, such as quasi-parallel and quasi-antiparallel stable states, out-of-plane precession, and bistable states can be realized. The precession frequency can be expressed as a function of the current and external magnetic field. In addition, the presence of field-like spin torque can change the switching current and precession frequency.

Using the nonequilibrium Hubbard operator Green's function technique, we study the inelastic low-temperature quantum transport through an artificial single-molecule magnet coupled to a single phonon mode. For a minimal model based on CdTe quantum dot doped with a single Mn 2+ ion ( S =5/2), the calculated results show that in the presence of hole–phonon coupling, in addition to main Kondo-like peaks associated with (2 S +1) sublevels of spin pair states, satellite Kondo-like peaks originating from emitting phonons appear in the local density of states and differential conductance. Moreover, the number of these phonon-induced Kondo-like peaks depends on the parity of the local large spin, i.e., S =integer or half-integer. It is expected that the intrinsic properties of artificial single-molecule magnets can be obtained by detecting these transport characteristics.

We extend the Green function approach to quantum transport through an anisotropic molecular magnet system with the help of Hubbard operators. Based on the single molecular magnet model, we reformulate the large spin and the total Hamiltonian in the language of Hubbard operators and obtain analytical expressions of the retarded Green function in sequential tunneling and Kondo regimes. In addition to this, we show the connection of our method to the master equation method in sequential regime and discuss a simple isotropic case in Kondo regime, in which we find a three-peak Kondo structure, a feature characterizing the isotropic exchange interaction between the localized electron and large spin.

We report the nonautonomous domain wall motion in ferromagnetic nanowire driven by spin-polarized current and magnetic field. Our results expatiate the major formation of domain wall velocity which comes from two parts: the longitudinal external field along the easy axis and the coherent domain wall rotation velocity. A critical condition is obtained analytically. Below the critical value, the domain wall rotation stops finally and domain wall velocity is proportional to the longitudinal external field. Above the critical value, the domain wall open out the novel nonautonomous helical motion characterized by the coherent rotation without any distortion. The domain wall velocity can be arbitrarily large for the linear proportion to longitudinal field strength.

A theoretical study is presented on the current-driven ferromagnetic resonance in the magnetic trilayers. On the basis of the Landau–Lifshitz–Gilbert–Slonczewski equation, we derive the output dc voltage for arbitrary anisotropy in the free and pinned layers by the linearization method. As an example, the resonance spectra of the tilted-polarizer and perpendicular-analyzer trilayer show that the equilibrium position, the resonant linewidth and the resonant location can be tuned by changing the magnitude and the direction of spin torque. The effective damping can be minimized through adjusting the current and the pinned-layer magnetization direction.

We report the use of liquid crystal 4-cyano-4′-biphenylcarbonitrile (5CB) doped with copper perchlorate as an optical sensor for detecting dimethyl methylphosphonate (DMMP) vapor. Our results show that after doping 5CB with copper perchlorate (0.05–50 mM), orientations of 5CB supported on plain glass slides gradually change from planar to homeotropic over time, and the time requires for turning homeotropic orientation increases with the decreasing concentration of copper perchlorate. When we expose a film of homeotropically oriented 5CB doped with 0.1 mM of copper perchlorate to 0.003 ppm of DMMP vapor, the optical appearance of 5CB changes from dark to bright in 2.5 min. In contrast, no response can be observed when the same film is exposed to 4500 ppm of water, 1000 ppm of ethanol or 1000 ppm of hexane. The optical response of 5CB to DMMP is fully reversible. Because DMMP is a commonly used simulant for chemical warfare agent, this work demonstrates the feasibility of using 5CB doped with copper perchlorate as a real-time gas sensor for detecting chemical warfare agents.

The magnetization dynamics is studied theoretically in the tilted-polarizer magnetic trilayers. Utilizing stability analysis, we obtain the phase diagrams in the plane defined by the current density and the direction of pinned-layer magnetization. With the pinned-layer magnetization oriented in a certain range, one can realize different magnetic states, such as quasi-parallel and quasi-antiparallel stable states, in-plane and out-of-plane precessions, and out-of-plane stable states by varying the current. We find that the free-layer magnetization prefers reversal for small deviation of the fixed-layer magnetization from the film plane, while precession for big deviation.

The optical-transport properties of 1D Se-doped CdS nanostructures with different doping contents and/or crystallization degrees are reported. The locally excited photoluminescence shows a significant redshift during the transport along the long axis of the 1D structures and can leave enough PL intensity for detection. The magnitude of the redshift is found to be highly dependent on the content of doping and the crystallization degree. The experimental results are compared with theoretical calculations based on the fundamental absorption rule of the semiconductor, which demonstrates that the redshift is related to the optical reabsorption effects induced by the local structural disorder in the semiconductors. Such optical properties of 1D semiconductor structures might be of interest for potential applications in color-tunable nanosized light-emitting and/or frequency-converting devices.

The effects of annealing temperature on TbFe films prepared by dc magnetron sputtering were discussed. X-ray diffraction patterns indicate that these polycrystalline films consisting mainly of α-Fe and TbFe2 lave phase with grain sizes less than 25 nm can be obtained by a rapid cycle annealing process. Grain sizes can be controlled by varying annealing temperatures. Film hysteresis loop studies show that annealing treatment can improve TbFe film in-plane soft magnetic performances. Magnetic domain structures explored by a magnetic force microscopy show that in the as-deposited films, maze domain structures exist, hence it possesses perpendicular anisotropy and larger anisotropic constant Ku. No domains are observed when annealing temperature is lower than 400 degrees C. However, maze domain structures appear again when annealing temperature is higher than 400 degrees C. Two maxima of magnetostrictive coefficients are obtained at annealing temperatures of 300 degrees C and 500 degrees C in the presence of a 40 kA.m−1 external magnetic field.

Current-driven domain wall dynamics is studied theoretically in the spin-valve nanostrips with parallel, perpendicular and tilted polarizers by Lagrangian formalism. In this description, the Slonczewski and field-like spin-transfer torques act as a Coulomb-type dissipation and an effective magnetic field, respectively. Considering a Walker profile, the wall behavior is governed by the dynamic equations about the center position, the out-of-plane angle, and the width of walls. It is found that the wall precesses after the steady motion breaks down for the parallel polarizer. The field-like spin-transfer torque favors a rapid increase of the steady velocity. The average velocity in the precession is nearly proportional to the current density. On the other hand, there is no precession for the perpendicular and tilted polarizers. Under the perpendicular polarizer, the wall stops when increasing current density. Moreover, there exist hysteresis and tri-stability for a large spin polarization. Under the tilted polarizer, it can be observed hysteretic, linear and nonlinear dependence of the wall velocity on the increasing current density. In the hysteresis, the wall experiences a switching of polarity or a reversal of motion.

Amorphous TbFe films are fabricated by dc magnetron sputtering, and their magnetostrictions at low field are examined over a wide range of terbium content (from 32 at.% to 70 at.%). It is found that the terbium content plays an important role in the magnetic and magnetostrictive properties of TbFe films. TbFe film soft magnetic properties and low field magnetostriction can be efficiently improved by controlling the terbium at an optimum content. The magnetostriction at lower magnetic field is increased with the increase of terbium content up to 48.2 at.%. After reaching the maximum value, further increase of terbium content would result in a great decrease of the low field magnetostriction. By contrast, at higher magnetic field, the magnetostriction is decreased monotonically with the increase of the terbium content.

We theoretically investigate the steady magnetic domain wall driven by spin-orbit torques in the heavy-metal/magnet bilayers with perpendicular anisotropy. Based on collective coordinates method and stability analysis, we analyze the effects of tilted current and Dzyaloshinskii-Moriya interaction on the wall. We find that the wall acquires a sustained motion in the high-current regime by deviating the current from the wall track. Also, a persistent motion can be supported by the competition between spin-orbit torques and Dzyaloshinskii-Moriya interaction in transforming wall type. In the low-current regime, there exist a switching of wall chirality and a reversal of wall motion.

The modulational instability and gap solitons are theoretically studied in the ferromagnetic films under a periodic magnetic field. By multiple scale expansion, the envelope soliton solutions are obtained naturally. Due to the periodic modulation of dispersion, the solitons may be pushed into the gap region. For the easy-axis magnetic film, the red-shift of frequency leads to a modulational instability in the bottom of band and generates a bright gap soliton. For the easy-plane case, the blue-shift leads to an instability in the top of band and a dark gap soliton emerges. The weak damping produces an attenuation factor and a small oscillation.

The steady motion of magnetic domain wall driven by spin-orbit torques is investigated analytically in the heavy/ferromagnetic metal nanowires for three cases with a current transverse to the in-plane and perpendicular easy axis, and along the in-plane easy axis. By the stability analysis of Walker wall profile, we find that if including the higher-order spin-orbit torques, the Walker breakdown can be avoided in some parameter regions of spin-orbit torques with a current transverse to or along the in-plane easy axis. However, in the case of perpendicular anisotropy, even considering the higher-order spin-orbit torques, the velocity of domain wall cannot be efficiently enhanced by the current. Furthermore, the direction of wall motion is dependent on the configuration and chirality of domain wall with a current along the in-plane easy axis or transverse to the perpendicular one. Especially, the direction of motion can be controlled by the initial chirality of domain wall. So, if only involving the spin-orbit mechanism, it is preferable to adopt the scheme of a current along the in-plane easy axis for enhancing the velocity and controlling the direction of domain wall.

We studied the static and dynamic domain wall solutions of spinor Bose-Einstein condensates trapped in an optical lattice. The single and double domain wall solutions are constructed analytically. Our results show that the magnetic field and light-induced dipolar interactions play an important role for both the formation of different domain walls and the adjusting of domain wall width and velocity. Moreover, these interactions can drive the motion of domain wall of Bose ferromagnet systems similar to that driven by the external magnetic field or the spin-polarized current in fermion ferromagnet., 5 pages, 3 figures

We present a theoretical investigation of ferromagnetic resonance in magnetic trilayers with tilted anisotropy. We find that the resonant magnetic field, the linewidth, the precessional frequency, and the axis of the magnetization in the free layer are all changed by the spin-polarized dc current in the presence of tilted pinned magnetization. Pumping and dissipation of energy in the magnetic system can be controlled by altering the current and the direction of pinned magnetization. The peak of ferromagnetic resonance excited by ac currents is sharpest with pinned magnetization perpendicular to the films, while it is almost flat in the parallel case.

We propose a scheme to investigate the magnetic phase transition of cold atoms confined in an optical lattice. We also demonstrate how to get coupled two-leg spin ladders which display a phase transition from a spin liquid to magnetic ordered state in two-dimensional optical lattice. An experimental protocol is further designed for observing this phenomenon.

We theoretically investigate the current-induced domain wall resonance in ferromagnetic nanowires with a Dzyaloshinskii-Moriya interaction. The adiabatic and nonadiabatic torques distort the wall's internal structure and exert a global pressure on the wall. An effective Newton's equation is obtained analytically for a domain wall moving in one-dimensional potential and subject to a viscous friction and a driving force. Our results demonstrate that the Dzyaloshinskii-Moriya interaction affects the critical current density for depinning the wall, resonance frequency, and amplitude.

Magnon density distribution can be affected by the spin-transfer torque in a perpendicular ferromagnetic anisotropy nanowire. We obtain the analytical expression for the critical current condition. For the cases of below and above the critical value, the magnon density distribution admits bright and dark soliton states, respectively. Moreover, we discuss two-soliton collision properties that are modulated by the current. Each magnetic soliton exhibits no changes in both velocity and width before and after the collision.

In NiFe/Pt bilayer, when spin current originating from the magnetization procession of NiFe is inject into the adjacent Pt layer under ferromagnetic resonance (FMR), the direct current (DC) voltage VISHE generated by inverse spin Hall effect (ISHE) will be added to the voltage VSRE generated by spin rectification effect (SRE), therefore the measured voltage in experiment is the sum of VISHE and VSRE. It is crucial to separate these contributions, which has been often overlooked before, in order to make a reasonable comparison of the ISHE among different materials. The voltages having symmetric (Lorentz type) and anti-symmetric (dispersive type) components both vary with the static magnetic field strength. However, they have different static magnetic field angle dependences according to our theoretical analysis. In order to distinguish the contribution of ISHE from that of SRE, in this paper, we employ a method, in which the voltage across the sample is measured when the static magnetic field is applied to different directions, to analyze the voltage by varying magnetic field angle in a range from 0° to 360° in steps of 10°, thereby separating the VISHE. The separation is carried out by fitting the angle dependent symmetric and anti-symmetric curves to different theoretical formulas of ISHE and SRE. The voltages of the two different contributions together with the phase angle of the microwave are obtained. At the same time, the FMR line width and the resonant field can be read out. The results show that the ferromagnetic resonance line width in NiFe(20 nm)/Pt(10 nm) sample is larger than that in NiFe(20 nm) sample due to the injection of spin current from NiFe to Pt in the bi-layer sample. We notice that in the curves of voltage vs. static magnetic field, the Lorentz symmetry components of the voltage from the bi-layer sample weight more than those from the single-layer sample. This is explained as a result of the existence of the ISHE in the bi-layer sample, where the spins are pumped from the magnetic layer to the adjacent nonmagnetic layer. The spin pumping effect does not show up in the single-layer sample. There are a large portion of symmetric components in the double layer sample, which is attributed to the ISHE. Although the voltage caused by the SRE is smaller than that by the ISHE, the SRE voltage cannot be ignored. Our work is crucial to understanding the spin-related effects in ferromagnetic/nonmagnetic metal material and provides an improved analysis method to study the spin pumping and the ISHE.

The influence of spin Hall effect on magnetization dynamics is one of the hottest topics in spintronics. In this paper, the magnetization dynamics driven by the spin Hall effect-induced torque in a ferromagnet /heavy metal bilayer structure has been investigated theoretically. By linearizing the Landau-Lifshitz-Gilbert equation which includes the spin Hall effect torque term, and taking stability analysis, the phase diagrams in the plane defined by the current density and external magnetic field have been obtained. Under the control of the current density and external magnetic field, several magnetic states, such as in-plane stable state, in-plane precession and bistable states can be realized. With the external magnetic field oriented within a certain range, the magnetization reversal and precession can be realized through adjusting the current density. In addition, the dynamic evolutions of these magnetic states are demonstrated by solving the temporal evolutive equations numerically.

We review our recent works on dynamics of magnetization in ferromagnet with spin-transfer torque. Driven by constant spin-polarized current, the spin-transfer torque counteracts both the precession driven by the effective field and the Gilbert damping term different from the common understanding. When the spin current exceeds the critical value, the conjunctive action of Gilbert damping and spin-transfer torque leads naturally the novel screw-pitch effect characterized by the temporal oscillation of domain wall velocity and width. Driven by space- and time-dependent spin-polarized current and magnetic field, we expatiate the formation of domain wall velocity in ferromagnetic nanowire. We discuss the properties of dynamic magnetic soliton in uniaxial anisotropic ferromagnetic nanowire driven by spin-transfer torque, and analyze the modulation instability and dark soliton on the spin wave background, which shows the characteristic breather behavior of the soliton as it propagates along the ferromagnetic nanowire. With stronger breather character, we get the novel magnetic rogue wave and clarify its formation mechanism. The generation of magnetic rogue wave mainly arises from the accumulation of energy and magnons toward to its central part. We also observe that the spin-polarized current can control the exchange rate of magnons between the envelope soliton and the background, and the critical current condition is obtained analytically. At last, we have theoretically investigated the current-excited and frequency-adjusted ferromagnetic resonance in magnetic trilayers. A particular case of the perpendicular analyzer reveals that the ferromagnetic resonance curves, including the resonant location and the resonant linewidth, can be adjusted by changing the pinned magnetization direction and the direct current. Under the control of the current and external magnetic field, several magnetic states, such as quasi-parallel and quasi-antiparallel stable states, out-of-plane precession, and bistable states can be realized. The precession frequency can be expressed as a function of the current and external magnetic field.

The dynamics of a domain wall induced by spin-polarized current is studied in ferromagnetic metallic thin films with stripe structures. The solution of the generalized Landau-Lifshitz-Gilbert equation including adiabatic and nonadiabatic spin torque is used to describe motion and distortion of the domain wall. We show that ac currents facilitate the manipulation of the domain wall since domain wall resonance decreases the critical current density for depinning. In contrast with dc current, both the two spin torques induced by ac currents can produce wall motion and distortion.

We investigate the effect of spin transport on nonlinear excitations in a ferromagnetic nanowire with nonuniform magnetizations. In the presence of spin-polarized current, the exact soliton solutions propagating along the wire's axis are obtained in two cases of high or low quality factors $(Q)$. The current can change the velocities of magnetic solitons and affect the solitons' collision with phase shift. Also, ac current induces vibration of the center of the solitons.

We investigate theoretically the current-driven domain wall dynamics in heavy-metal-ferromagnet bilayers. Within Lagrangian formalism, the influence of spin Hall effect on the behavior and stability of Walker's profile is analyzed. We find that in the high-current regime, although the spin Hall current alters the wall mobility slightly, the Walker breakdown is removed. In the low-current regime, the spin Hall effect makes the wall motion dependant on the polarity. The static Neel wall can be transformed into Bloch one and the polarity of Bloch wall can be switched. Especially, for proper initial polarity and current, the wall propagates along the current direction.