Field-induced structural transition and irreversible domain detwinning in the antiferromagnet Fe1.1Te

Abstract

Single-crystal x-ray diffraction in pulsed magnetic fields of up to 31 T was used to investigate the iron telluride antiferromagnet Fe1.1Te, which is a parent of the Fe-based chalcogenide superconductors. At temperatures below the Néel temperature TN≃60 K, high magnetic fields perpendicular to the c axis lead to an irreversible detwinning of the crystal at the field HR, where magnetocrystalline domains are selected by a moment reorientation process. Just below TN, the onset of a structural transition at the critical field HC>HR, which delimits the antiferromagnet phase, indicates a partial restoration of the high-temperature tetragonal symmetry. The lattice and magnetic answers to an in-plane magnetic field are discussed, emphasizing the strength of magnetoelastic coupling in Fe1.1Te.