Canted antiferromagnetism in the quasi-one-dimensional iron chalcogenide BaFe 2 Se 4

We report the synthesis and physical properties studies of quasi-one-dimensional (quais-1D) iron chalcogenide ${\mathrm{BaFe}}_{2}{\mathrm{Se}}_{4}$ which shares the ${\mathrm{FeSe}}_{4}$ tetrahedra building motif commonly seen in the iron chalcogenide superconductors. A high-quality polycrystalline sample was achieved by solid-state reaction method and characterized by x-ray diffraction, electrical resistivity, magnetic susceptibility, and neutron diffraction measurements. ${\mathrm{BaFe}}_{2}{\mathrm{Se}}_{4}$ is a narrow gap semiconductor that magnetically orders at $\ensuremath{\sim}310$ K. Both neutron powder diffraction results and isothermal $M\ensuremath{-}H$ loops suggest a canted antiferromagnetic structure where Fe sublattices are antiferromagnetically ordered along the $c$-axis quasi-1D chain direction, resulting in a net ferromagnetic moment in the perpendicular direction along the $a$ axis with tilted angle of $18.{7}^{\ensuremath{\circ}}$ towards the $b$ axis.