The magnetic, thermal transport properties, magnetothermal effect and critical behavior of Co₃Sn₂S₂ single crystal

Abstract

Through the magnetic/thermal transport measurements combined with the analyses of magnetocaloric effect and critical behavior of Co3Sn2S2 single crystal, the main results we obtained are as follows: in the case of the magnetic field H//c‐axis, Co3Sn2S2 exhibits the phase‐separation state below Tc in the low‐field region (H < 500 Oe). Tc increases slightly from 174 to 177 K with an increase in H from 100 to 10 kOe. The second‐order magnetic phase transition near Tc and the itinerant ferromagnetism below Tc are identified. The magnetization below Tc matches well with the three‐dimensional Ising model, instead of the mean‐field model. In the case of H//ab, Tc changes between 175 and 178 K with varying H. Noticeably, M above Tc exhibits a small positive value, instead of the null M as commonly expected in the paramagnetic region. An extra phase transition below 166 K is observed. The magnetic transition near Tc seems not to be the second‐order phase transition. All results show a significant characteristic of anisotropic magnetic phase transition for the Co3Sn2S2 single crystal. They support mutually those in previous reports, moreover, some new phenomena are also observed. They also provide the experimental evidences for the deep insight into the magnetic phase–transition behavior of Co3Sn2S2.

Anomalous depinning of magnetic domain walls within the ferromagnetic phase of the Weyl semimetal Co3Sn2S2

“…First, the FCC and FCW curves start to deviate near T C . Second, a local maximum arises at T A ≈ 130 K in the FCC data, which is also reported in other studies [10][11][12][13][14][15][16]18]. The local maximum disappears above 300 Oe and below 50 Oe, while a small hysteresis between FCC and FCW still remains at 50 Oe.…”

“…Co 3 Sn 2 S 2 crystallizes in a hexagonal lattice with triangular S and Sn layers interspersed between the kagome lattice planes of Co. The magnetic structure of this compound is still under investigation due to an anomaly in its magnetization occurring around 130 K upon cooling [10][11][12][13][14][15][16]. Various interpretations have been proposed to explain the anomaly.…”

Tuning the anomalous Nernst and Hall effects with shifting the chemical potential in Fe-dope and Ni-doped Co$_3$Sn$_2$S$_2$

“…. Here γ = 1.59 mJ/(molK 2 ) [40] is the Sommerfeld coefficient and n = 8.8×10 25 cm −3 [31] is the carrier density. If the only carriers were electrons (holes), the expected S xx /T would have been −(+)1.2µV/K 2 .…”

Tuning the anomalous Nernst and Hall effects with shifting the chemical potential in Fe-doped and Ni-doped Co3Sn2S2

“…The average Fermi energy of a pocket can be estimated to be ≈20 meV using E F = π 2 navek 2 B 2γ . Here γ = 1.59 mJ (mol K 2 ) −1 [40] is the Sommerfeld coefficient and n = 8.8 × 10 25 cm −3 [31] is the carrier density. If the only carriers were electrons (holes), the expected S xx /T would have been −(+)1.2 µV K −2 .…”