Anomalous Hall effect in thin films of the Weyl antiferromagnet Mn3Sn

Abstract

The Weyl antiferromagnet Mn3Sn has recently attracted significant attention as it exhibits various useful functions such as large anomalous Hall effect that are normally absent in antiferromagnets. Here we report the thin film fabrication of the single phase of Mn3Sn and the observation of the large anomalous Hall effect at room temperature despite its vanishingly small magnetization. Our work on the high-quality thin film growth of the Weyl antiferromagnet paves the path for developing the antiferromagnetic spintronics.

Room-temperature terahertz anomalous Hall effect in Weyl antiferromagnet Mn3Sn thin films

“…Figure 1c presents the X-ray diffraction (XRD) patterns of the 50-nm-thick film of Mn3+xSn1-x (x=0.02) on the SiO2 substrate obtained by the grazing angle XRD measurement. All the peaks can be indexed by the hexagonal D019 Mn3Sn structure and no additional peaks coming from plausible impurity phases are observed, which is consistent with that in the films on a thermally oxidized Si substrate 35 . Figure 1d provides a schematic diagram of our sample configuration.…”

“…Figure 3e exhibits Re ( ) averaged between 2-10 meV as a function of temperature. As the temperature decreases, Re ( ) is sharply suppressed around 250 K. The similar sharp reduction of the AHE as well as magnetization has been also observed in the DC measurement 35 . Such a spin-reorientation phase transition has been studied by neutron scattering experiments, which have revealed that the 120-degree spin order in each ab plane rotates to form a helical spin ordering along the c-axis below 250 K 46 .…”

“…In the present experiment, the Hall conductivity can be clearly observed as light polarization rotation in a noncontact fashion without using magnetic field. We also confirmed that the polarization rotation was unchanged even several months after the sample fabrication and magnetization, exhibiting robustness of magnetic information in the Mn3Sn thin films 35 . To investigate in broader frequency range, we also performed the same polarization-resolved THz-TDS for a 50-nm Mn3+xSn1-x (x=0.08) on a Si substrate at room temperature by using (110) GaP crystals and 20-fs laser pulses with 1-kHz repetition (See Methods).…”

“…Sample. Samples used in this work are polycrystalline Mn3+xSn1-x thin films (x=0.00, 0.02, and 0.08) deposited on SiO2 or thermally oxidized Si substrates by DC magnetron sputtering 35 .…”

“…Therefore, low-energy THz polarimetry will provide deep insight into the microscopic picture of the large AHE in the Weyl semimetal. In this work, using Mn3Sn thin films showing the large AHE comparable to the bulk35 , we perform…”