Electrical manipulation of a topological antiferromagnetic state

Area of Science:

• Condensed Matter Physics
• Materials Science
• Spintronics

Background:

• Topological materials, like Weyl semimetals, offer robust phenomena due to protected band topology.
• Magnetic Weyl semimetals are crucial for controlling topological properties, enabling antiferromagnetic spintronics.
• Electrical control of Weyl metals has remained an unachieved goal, hindering technological applications.

Purpose of the Study:

• To demonstrate the electrical switching of a topological antiferromagnetic state.
• To detect this switching via the anomalous Hall effect (AHE) at room temperature.
• To explore the potential for antiferromagnetic spintronics using Weyl metals.

Main Methods:

• Fabrication of polycrystalline thin films of the antiferromagnetic Weyl metal Mn3Sn.
• Utilizing bilayer devices with Mn3Sn and nonmagnetic metals (Pt, Cu, W).
• Applying electrical current densities (10^10 to 10^11 A/m^2) to induce magnetic switching and measuring Hall voltage.

Main Results:

• Successful electrical switching of the topological antiferromagnetic state in Mn3Sn at room temperature.
• Detection of switching via a significant change in Hall voltage, demonstrating zero-field AHE.
• Observation that current polarity and the spin Hall angle of adjacent nonmagnetic metals determine the Hall voltage sign.

Conclusions:

• The study achieved electrical control of an antiferromagnetic Weyl metal, a significant advancement.
• The findings support the use of antiferromagnetic spintronics for high-density, ultrafast devices.
• This work opens new avenues for topological magnetism and advanced electronic technologies.