This letter presents an efficient dipole coupled nanomagnetic logic scheme clocked by voltage-induced stress. The logic signals can be transmitted to an array of eight elliptical nanomagnets in one cycle. Transmission speed is increased 1-2 times versus the conventional stress scheme while the required stress is reduced. Micromagnetic simulations illustrate that both increasing the tilt angleof the electrode pair and decreasing the nanomagnet thickness can reduce the stress. When the nanomagnet thickness is 8 to 12 nm and the tilt angle of the electrode pair is 8° to 10°, it is a tradeoff considering the stress, reliability, and fabrication.

Experimental investigations of ultrafast electro-optical properties in magnetic materials manifest their great potential for emerging spintronic optoelectronic devices. Here, using time-resolved terahertz emission spectroscopy, we construct a spintronic terahertz emitter consisting of an ${\mathrm{Ir}\mathrm{Mn}}_3/\mathrm{Ni}-\mathrm{Fe}$ heterojunction. A femtosecond spin current pulse is generated in the thin film of the $\mathrm{Ni}-\mathrm{Fe}$ layer when it absorbs a femtosecond laser pulse, and then the spin current is converted into a transient charge current by the metallic ${\mathrm{Ir}\mathrm{Mn}}_3$ layer on picosecond timescales. We timely record the terahertz emission associated with this ultrafast conversion process by means of electro-optic sampling. Besides, the spin-to-charge conversion efficiency of the ${\mathrm{Ir}\mathrm{Mn}}_3/\mathrm{Ni}-\mathrm{Fe}$ heterojunction is determined via quantitative analysis of the spin torque ferromagnetic resonance results. We have both optically verified and electrically studied the spin-to-charge conversion of the ${\mathrm{Ir}\mathrm{Mn}}_3/\mathrm{Ni}-\mathrm{Fe}$ heterojunction. Our results enlarge the material choice range of spintronic terahertz emitters, which may promote further investigations of ultrafast spin-to-charge conversion in different heterojunction materials.

In this paper, we propose a performance optimization scheme for all-spin logic device (ASLD); this scheme makes use of asymmetric tunneling layer to overcome the conductivity mismatch problem. Besides, for the material selection of device, this scheme makes advantage of silver as an energy efficient interconnect material to reduce the switching delay. The simulation results indicate that the high spin injection efficiency can be obtained by increasing the thickness of the transmitter-side tunneling layer or decreasing the thickness of the receive-side tunneling layer. Therefore, the structure of asymmetric tunneling layer is expected to be more effective for spin injection. Compared with the traditional interconnect that copper or aluminum is used as a channel material, the time for magnetic moment reversal and the spin current flowing into the output magnet are predicated to be optimized when silver is chosen as the channel material, which can attribute to the fact that the conductivity of silver material is larger, the spin diffusion length is longer, and the spin-orbit interaction is weaker. Meanwhile, when the critical switching current requires for the magnetization reversal is applied, the reliable working length of silver channel is significantly longer than that of copper or aluminum channel. These abovementioned results provide a new method for the performance optimization of ASLD.

We propose an effective magnetic vortex polarity reversal scheme that makes use of spin-orbit torque introduced by spin-Hall effect in heavy-metal/ferromagnet multilayers structure, which can result in subnanosecond polarity reversal without endangering the structural stability. Micromagnetic simulations are performed to investigate the spin-Hall effect driven dynamics evolution of magnetic vortex. The mechanism of magnetic vortex polarity reversal is uncovered by a quantitative analysis of exchange energy density, magnetostatic energy density, and their total energy density. The simulation results indicate that the magnetic vortex polarity is reversed through the nucleation-annihilation process of topological vortex-antivortex pair. This scheme is an attractive option for ultra-fast magnetic vortex polarity reversal, which can be used as the guidelines for the choice of polarity reversal scheme in vortex-based random access memory.

In this paper, the in situ control of radial vortex polarity and chirality at room temperature mediated by perpendicular magnetic field pulse has been reported via micromagnetic simulations. The correlative results show that the polarity and chirality are switched simultaneously without resulting in a large core movement, the simulation built-in magnetic force microscopy provides a deeply insight into the evolution of magnetic configuration during the reversal process. The reversal mechanism reported in this work differs from the reported vortex-antivortex pair creation and annihilation mechanisms, which is useful for bit reading and probing in magnetic data storage devices. Meanwhile, the thermal perturbations at nonzero temperatures will weaken the effect of magnetic field, so the threshold field strength need increase with the elevated temperature to guarantee chirality and polarity reversed completely. This approach presents an alternative efficient means to achieve an ultrafast radial vortex chirality and polarity switching, which paves the way for the practical application of magnetoresistive memory based on radial vortex.