FeS: Structure and Composition Relations to Superconductivity and Magnetism

Abstract

Structure and composition of iron chalcogenides have a delicate relationship with magnetism and superconductivity. In this report we investigate the iron sulfide layered tetragonal phase (t-FeS), and compare with three-dimensional hexagonal phase (h-FeS). X-ray diffraction reveals the absence of structural transitions for both t- and h-FeS below room temperature, and gives phase compositions of Fe0.93(1)S and Fe0.84(1)S, respectively, for the samples studied here. The a lattice parameter of bigger than 3.68 A is significant for causing bulk superconductivity in iron sulfide, which is controlled by composition and structural details such as iron stoichiometry and concentration of vacancy. While h-FeS with a = 3.4436(1) A has magnetic ordering well above room temperature, our t-FeS with a =3.6779(8)A shows filamentary superconductivity below Tc = 4 K with less than 15% superconducting volume fraction. Also for t-FeS, the magnetic susceptibility shows an anomaly at ~ 15 K, and neutron diffraction reveals a commensurate antiferromagnetic ordering below TN = 116 K, with wave vector km= (0.25,0.25,0) and 0.46(2)uB/Fe. Although two synthesis routes are used here to stabilize t vs h crystal structures (hydrothermal vs solid-state methods), both FeS compounds order on two length-scales of ~1000 nm sheets or blocks and ~ 20 nm smaller particles, shown by neutron scattering. First principles calculations reveal a high sensitivity to the structure for the electronic and magnetic properties in t-FeS, predicting marginal antiferromagnetic instability for our compound (sulfur height of zS ~0.252) with an ordering energy of ~11 meV/Fe, while h-FeS is magnetically stable.

14 pages, 7 figures

References in corpus (11)

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Cited by in corpus (10)

• Quantum Magnetism in Minerals
• Phonon anomalies in FeS
• Two-dome superconductivity in FeS induced by a Lifshitz transition
• Topological crystalline antiferromagnetic state in tetragonal FeS
• Multi-layered chalcogenides with potential for magnetism and superconductivity
• Observation of a C-type short range antiferromagnetic order in expanded FeS
• Thermoelectricity and electronic correlations enhancement in FeS by slight Se substitution
• Accurate determination of the Fermi surface of tetragonal FeS via quantum oscillation measurements and quasiparticle self-consistent \textit{GW} calculations
• Superconductivity with Tc=7 K under pressure for Cu-, and Au-doped BaFe2As2
• Predictability as a probe of manifest and latent physics: The case of atomic scale structural, chemical, and polarization behaviors in multiferroic Sm-doped BiFeO3