Modulation of magnetism in a Weyl semimetal using current-assisted domain wall motion

Spintronic devices are emerging technologies that exploit the intrinsic spin of electrons to store and process data. These technologies have the potential to outperform conventional electronics in speed and power efficiency.

A team of researchers from Peking University, the Chinese Academy of Sciences and other institutes in China have recently introduced an approach that could potentially help improve the efficiency of spintronics devices. Their strategy, set out in an article published in Natural electronicsinvolves the modulation of magnetism in a magnetic Weyl semimetal, which in turn could displace the domain wall, the region in a ferromagnetic material where the direction of the magnetization changes.

“The efficiency of spintronic devices can be improved by generating higher effective magnetic fields with lower working currents,” Quiyuan Wang and colleagues wrote in their paper. “Spin transfer torques can drive the motion of the magnetic domain wall in a single-material device, but a high threshold current density is usually required to move the domain wall and field enhancement. effective magnetic in common traveling ferromagnets is difficult.”

Wang and his colleagues essentially devised an approach to modulate the magnetism in Co₃sn₂S₂, a magnetic Weyl semimetal. Magnetic Weyl semimetals are materials that host exotic quasiparticles, called Weyl fermions. these crystalline solids have sometimes been proposed as potential candidate materials for the development of spintronic devices.

The strategy proposed by the researchers specifically involves the movement of the so-called domain wall via a phenomenon called spin-transfer-torque, which occurs in ferromagnetic materials. In spintronics research, spin transfer torque is used to manipulate the magnetization of materials, allowing devices to store and process data more efficiently.

To test the effectiveness of their method, the team collected a series of measurements and performed several simulations. Their findings were very promising, highlighting the tremendous potential of Weyl’s magnetic semimetals to create new spintronic devices.

“We examine the effect of direct current on magnetic reversal using anomalous Hall resistance measurements and domain wall motion using time-of-flight measurements,” Wang and colleagues wrote in their article. “At 160 K, the threshold the current density to drive the motion of the domain walls is less than 5.1 × 10⁵ one centimeter⁻² at zero external field and less than 1.5 × 10⁵ one centimeter⁻²at a moderate external field (0.2 kOe). The effective spin transfer torque field can reach 2.4 to 5.6 kOe MA⁻¹cm²at 150K.”

Using spin transfer-assisted domain wall propagation, Wang and co-workers were able to modulate the process of magnetization reversal in Co₃sn₂S₂ low current density nanoflakes. Further analyzes revealed that the unique parameters of Co₃sn₂S₂ are particularly favorable to allow the movement of the walls of the domain.

While the researchers’ study focused on Co₃sn₂S₂ the same approach could also be used to move domain walls in other magnetic Weyl semi-metals, potentially allowing for greater device efficiency. In the future, their work could thus pave the way for the creation of a new set of more energy-efficient devices. spintronic devices based on these promising materials.

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