Large Hall Signal due to Electrical Switching of an Antiferromagnetic Weyl Semimetal State

Developing a technology to electrically manipulate a Weyl semimetal state is a vital step for designing a nonvolatile memory using topologically robust properties. Recently, such manipulation is realized for the first time in the antiferromagnetic Weyl semimetal Mn3Sn using the readout signal of anomalous Hall effect in the Mn3Sn/heavy metal (Pt, W) heterostructures. Here, it is reported that the switching of Hall signal can be significantly enhanced by 1) removing the buffer layer of Ru to adjust the crystal orientation of Mn3Sn, and 2) annealing after deposition of the heavy metal to change the interfacial condition. The switching of the Hall resistance is 0.35 Ω in the Mn3Sn/W sample, which becomes one order of magnitude larger than the previously reported value using Ru/Mn3Sn/Pt heterostructures. Moreover, by increasing the read current, it is found that the readout voltage may go well beyond 1 mV, a milestone for future applications in memory technology. Antiferromagnets attract tremendous interest for spintronics application due to their small stray fields and fast dynamics. Antiferromagnetic Weyl semimetal Mn3Sn/heavy metal heterostructures can act as nonvolatile memory where the readout Hall voltage can be switched electrically. This study reports that this readout signal can be significantly enhanced to the order of millivolts by adjusting their crystal orientation and interfacial condition.