Magnetic properties of FexV3−xS4 (0 ≤ x ≤ 2)

The magnetic susceptibility data of Fe_xV_3?xS₄ (0 ≤ x ≤ 2) are reported in the temperature range between 4.2 and 1300 K. The behavior of the susceptibility at high temperatures changes significantly at the composition boundary x = 1.0. The magnitude of the effective magnetic moment remains unchanged at 3.2 μ_B in the composition range x < 1.0. It decreases with increasing iron content in the range > 1.0, and rapidly decreases for x close to 2.0. The c lattice parameter varies in a manner analogous to the change in magnetic moment. These phenomena suggest that metallic bonding forms between metal layers and that it becomes stronger with increasing in x. The susceptibility measurements at low temperatures show that Fe_xV_3?xS₄ is basically antiferromagnetic, although some of the Fe_xV_3?xS₄ compounds become weakly ferromagnetic after cooling in a magnetic field. The origin of the weak ferromagnetism is briefly discussed.