Magnetic structure ofNiS2−xSex

Abstract

${\mathrm{NiS}}_{2\ensuremath{-}2x}{\mathrm{Se}}_{x}$ is revisited to determine the magnetic structure using neutron diffraction and magnetic representational analysis. Upon cooling, the insulating parent compound, ${\mathrm{NiS}}_{2}$, becomes antiferromagnetic with two successive magnetic transitions. The first transition $(M1)$ occurs at ${T}_{N}\ensuremath{\sim}39\phantom{\rule{4pt}{0ex}}\text{K}$ with ${\mathrm{\ensuremath{\Gamma}}}_{1}{\ensuremath{\psi}}_{1}$ symmetry and a magnetic propagation vector of $k=(000)$. The second transition $(M2)$ occurs at ${T}_{N}\ensuremath{\sim}30\phantom{\rule{4pt}{0ex}}\text{K}$ with $k=(0.5,0.5,0.5)$ and a ${\mathrm{\ensuremath{\Gamma}}}_{1}{\ensuremath{\psi}}_{2}$ symmetry with face-centered translations, giving rise to four possible magnetic domains. With doping, the system becomes metallic. The transition to the $M2$ state is suppressed prior to $x\phantom{\rule{4pt}{0ex}}=0.4$ while the $M1$ state persists. The $M1$ magnetic structure gradually vanishes by $x\ensuremath{\sim}0.8$ at a lower concentration than previously reported. The details of the magnetic structures are provided.