On the anisotropies of magnetization and electronic transport of magnetic Weyl semimetal Co3Sn2S2

Abstract

Co 3 Sn 2 S 2 , a quasi-two-dimensional system with kagome lattice, has been found as a magnetic Weyl semimetal recently. In this work, the anisotropies of magnetization and transport properties of Co 3 Sn 2 S 2 were investigated. The high field measurements reveal a giant magnetocrystalline anisotropy with an out-of-plane saturation field of 0.9 kOe and an in-plane saturation field of 230 kOe at 2 K, showing a magnetocrystalline anisotropy coefficient K u up to 8.3 × 10 5 J m -3 , which indicates that it is extremely difficult to align the small moment of 0.29 μ B /Co on the kagome lattice from c axis to ab plane. The out-of-plane angular dependences of Hall conductivity further reveal strong anisotropies in Berry curvature and ferromagnetism, and the vector directions of both are always parallel with each other. For in-plane situation, the longitudinal and transverse measurements for both I // a and I  a cases show that the transport on the kagome lattice is isotropic. These results provide essential understanding on the magnetization and transport behaviors for the magnetic Weyl semimetal Co 3 Sn 2 S 2 .

Spin excitations and spin wave gap in the ferromagnetic Weyl semimetal Co3Sn2S2

“…(b)).Finally, we estimate the spin anisotropy energy by calculating the energy difference when all the local moments are rotated from the ground state to the same angle within the xoz plane or xoy plane. The maximum energy obtained between two geometries (∼0.6 meV) is consistent with the magnetization results (inset of Figure3(b))[17,50].…”

33% Giant Anomalous Hall Current Driven by Both Intrinsic and Extrinsic Contributions in Magnetic Weyl Semimetal Co3Sn2S2

“…The magnetic moments of Co atoms are fixed on the kagome layer in the ab-plane and along the c-axis. [29] The room-temperature XRD patterns of Co3-xFexSn2S2 show only the (000l) Bragg peaks, which indicates that the exposed plane surface is the ab-plane, as shown in Figure 1b. Moreover, the peaks (000l) shift to lower diffraction angles with increase in the Fe content, as illustrated in inset of Figure 1b.…”

“…The AHA at 10 K also demonstrates a similar Fe-doping dependence, as shown in Figure 2d, exhibiting a maximum of 33% at x = 0.15 under zero field, which is considerably larger than that of any magnetic bulk material reported previously. Figure 2e shows the temperature dependence of the AHC at 1 kOe (larger than the out-ofplane saturation field of 0.9 kOe) [29] from 10 to 300 K (also see Figure S3). As the AHC at x = 0 is basically dominated by the Berry curvature of the topological band structures, the AHC remains unchanged below 100 K. [17] With further increase in temperature, the increase in thermal disturbance initiates the random arrangement of magnetic moments, which reduces the strength of the Berry curvature and AHC.…”

On the anomalous low-resistance state and exceptional Hall component in hard-magnetic Weyl nanoflakes

“…The Curie temperatures of the two selected samples were determined as 181 K through the kink temperature in the temperature-dependent resistivity curve (Supporting Information Note 2). The single-crystalline Co 3 Sn 2 S 2 nanoflakes being studied show consistent basic physical properties with bulk single crystals [1,21] (Supporting Information Note 4). Furthermore, the nanoflakes show high quality with a residual resistivity ratio of~20, an anomalous Hall conductivity of~1000 Ω −1 m −1…”

“…Theoretical calculations show that there could be bound states and potential current, which are highly localized around a magnetic domain wall or texture [16,17,20]. In experiments, Co 3 Sn 2 S 2 bulk samples indeed showed other possible magnetic interactions besides the out-of-plane ferromagnetic interaction, and thus, nonuniform magnetization behavior below the Curie temperature [1,21,36,37]. A roundshaped domain structure has also been observed in the Co 3 Sn 2 S 2 system [38].…”