Physical Review Letters · 2008 · 512 citations · 7 references
Natural SciencesMaterials SciencePhysicsCondensed Matter PhysicsMagnetic MaterialsSolid State PhysicsAntiferromagnetismExchange InteractionsFerromagnetismMagnetic Properties Of SolidsMagnetism In SolidsPhase TransitionsAntiferromagnetic OrderAntiferromagnetic OrderingFrustrated Exchange InteractionsFrustrated MagnetismMagnetic Exchange InteractionsSpin FrustrationStructural Phase TransitionsTetragonal System
Large, frustrated antiferromagnetic exchange between Fe ions suggests strong coupling of magnetism and superconductivity in doped LaFeAsO, analogous to cuprates. Fixed‑spin‑moment calculations show that the stripe antiferromagnetic state with M(Fe)=0.48 μB is the only stable ground state, breaking tetragonal symmetry, relieving frustration, and producing the structural distortion that accounts for the magnetic and structural transitions seen by neutron scattering.
From all-electron fixed-spin-moment calculations we show that ferromagnetic and checkerboard antiferromagnetic ordering in LaFeAsO are not stable and the stripe antiferromagnetic configuration with M(Fe)=0.48 microB is the only stable ground state. The main exchange interactions between Fe ions are large, antiferromagnetic, and frustrated. The magnetic stripe phase breaks the tetragonal symmetry, removes the frustration, and causes a structural distortion. These results successfully explain the magnetic and structural phase transitions in LaFeAsO recently observed by neutron scattering. The presence of competing strong antiferromagnetic exchange interactions suggests that magnetism and superconductivity in doped LaFeAsO may be strongly coupled, much like in the high-T(c) cuprates.
7
Yoichi Kamihara, Takumi Watanabe, Masahiro Hirano et al. · Journal of the American Chemical Society · 2008 · 7.9K citations
Magnetic order close to superconductivity in the iron-based layered LaO1-xF x FeAs systems
Clarina dela Cruz, Q. Huang, J. W. Lynn et al. · Nature · 2008 · 1.8K citations · Full text