Electric field control of magnetization direction across the antiferromagnetic to ferromagnetic transition

Reconfigurable Skyrmion-Based Logic Gates: Versatile Design and Full-Scale Implementation

Herein, we investigate the behavior of skyrmions within a racetrack design incorporating voltage-controlled magnetic anisotropy (VCMA) gates. Our analysis encompassed multiple forces, including spin currents and anisotropy gradients induced by bias voltages. As a result, the efficient control of skyrmion dynamics was achieved across various VCMA gate configurations. Building upon these findings, we propose an efficient approach to reconfigurable skyrmion logic (RSL) in a thin antiferromagnetic (AFM) film through a versatile design. Our RSL harnesses the selective integration of VCMA, spin-polarized currents, and skyrmion-skyrmion (sky-sky) interactions to implement multiple logic gates, including AND, OR, XOR, NOT, NAND, XNOR, and NOR. The design brings a significant advantage with its simplified fabrication process, making the implementation of the RSL practical and accessible for various applications. Furthermore, the RSL enables seamless dynamic switching between logic gates, thereby enhancing its multifunctionality. Additionally, the strategic incorporation of sky-sky interactions and skyrmion-edge repulsion prominently facilitates the realization of complex gates, such as NAND, XNOR, and NOR gates, that typically require intricate design efforts. Hence, this streamlined integration of RSL, coupled with its adaptability to changing computational needs, underscores its potential as a practical solution for implementing high-functionality skyrmion-based logic gates.

Electrically induced net magnetization in FePSe3 nanoribbons: the role of edge reconstructions

Magnetized edge states of nanoribbon systems open a new path for designing functional spintronic devices. Here, we introduce a general mechanism for electrically generating nonzero net magnetization in antiferromagnetic (AFM) semiconducting nanoribbons. In the proposed spin configuration, in which the empty and occupied edge states of one side close to the Fermi energy are in the same spin channel, the Zeeman-type spin splitting between the states of opposite edges arising from the electric field allow the system to be tuned from the AFM semiconducting phase to the ferromagnetic (FM) metallic phase, yielding nonzero net magnetization. Our ab initio calculations show that this strategy is realizable in the example of the FePSe3 nanoribbon, in which self-passivation-driven reconstruction at the Se termination edge gives rise to the key spin configuration. Moreover, we demonstrate that an electric field could trigger a series of electronic phase transitions among AFM semiconductor, AFM half-metal, and FM metal phases, based on which we were able to design an electronically controllable versatile spintronics device.

Recent developments on the magnetic and electrical transport properties of FeRh- and Rh-based heterostructures

It is fascinating how the binary alloy FeRh has been the subject of a vast number of studies almost solely for a single-phase transition. This is, however, reasonable, considering how various degrees of freedom are intertwined around this phase transition. Furthermore, the tunability of this phase transition-the large response to tuning parameters, such as electric field and strain-endows FeRh huge potential in applications. Compared to the bulk counterpart, FeRh in the thin-film form is superior in many aspects: materials in thin-film form are often more technologically relevant in the first place; in addition, the substrates add extra dimensions to the tunability, especially when the substrate itself is multiferroic. Here we review recent developments on the magnetic and transport properties of heterostructures based on FeRh and its end-member Rh, with the latter providing a new route to exploiting spin-orbit interactions in functional spintronic heterostructures other than the more often employed 5dmetals. The methods utilized in the investigation of the physical properties in these systems, and the design principles employed in the engineering thereof may conceivably be extended to similar phase transitions to other magnetic materials.