Spin Structure and Magnetic Properties of NiS₂

Abstract

Magnetization curves of single crystals were measured from 4.2 K up to T_c (\simeq30 K). The magnetization is approximately expressed by M=M₀+χ_wH in higher fields. χ_w which reflects the antiferromagnetic character, was found to be almost isotropic and temperature-independent (\simeq8×10⁻⁶ emu/g). M₀ is anisotropic; 0.97 emu/g (0.02 μ_B/Ni) along [001] and 0.69 emu/g along [110] at 4.2 K. The magnetic field effect on the intensity of neutron diffraction was examined on single crystals. Any appreciable effect was not found within experimental errors on two antiferromagnetic reflections. An improved model (model 3) for the spin structure is proposed, which explains the observed intensities of neutron diffraction, Mössbauer study and the behavior of χ_w.