Hall effect of itinerant electron metamagnet Co(S1-xSex)2

•Magnetic field dependence of Hall effect was examined for Co(S1-xSex)2 with 0.08 ≤ x ≤ 0.14, which shows itinerant electron metamagnetism. From the analyses of the Hall data and the magnetization curves, the normal Hall coefficients were estimated in the ferromagnetic state as well as in the paramagnetic state.•It is found that the normal Hall coefficient in the ferromagnetic state is 31–39 × 10-11 m3/C and that in the paramagnetic state is 10–20 × 10-11 m3/C. These normal Hall coefficients show weak temperature dependence below 70 K.•The normal Hall coefficient of each magnetic state was evaluated from the energy band calculations for CoS2. The calculated coefficient of ferromagnetic CoS2 is comparable to the experimental values, while that of nonmagnetic CoS2 is definitely smaller that the experimental values in the paramagnetic state. The origins of this discrepancy were discussed from both experimental and theoretical sides. We have studied the Hall effect of Co(S1-xSex)2 with 0.08 ≤ x ≤ 0.14, which shows itinerant electron metamagnetism (IEM). The Hall resistivity ρxy was measured as a function of the magnetic field B at various temperatures. It is found that ρxy decreases nearly linearly with increasing B in the paramagnetic state, while it has a positive slope in the ferromagnetic state. Abrupt drops were observed at around the metamagnetic transition field in the ρxy – B curves, which are attributable to the anomalous Hall effect. From the analyses of the ρxy – B curves and the magnetization curves, we estimated the anomalous Hall coefficient, the normal (ordinary) Hall coefficient in the ferromagnetic state, and that in the paramagnetic state. Appearance of both ferromagnetic and paramagnetic states depending on a magnetic field in IEM makes it possible to estimate these values, simultaneously. The estimated normal Hall coefficients are compared with the theoretical values calculated from the energy band structures. The present study has demonstrated that IEM provides a suitable stage to understand the electronic structures of both ferromagnetic and paramagnetic states of the itinerant electron system at the same temperature.