Evidence for local moments by electron spin resonance study of polycrystallineLaFeAsO1−xFx(x=0and 0.13)

2008/11/16 by T. Wu, Tao Wu, J. J. Ying +15
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paper · pdf · doi:10.1103/physrevb.79.115121

published as Phys. Rev. B 79, 115121(2009) · 5 pages, 5 figures

arxiv created 2008/11/16 · openalex publication_date 2009/03/20 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05

Abstract

The temperature dependence of electron spin resonance was studied in the oxypnictide superconductors LaFeAsO_1\ensuremath-xF_x (x=0 and 0.13). In the samples, the ESR signal indicates that the g factor and peak-to-peak linewidth strongly depend on temperature, especially at low temperatures. It indicates a strong-coupling picture with existence of local moment. The dependence mentioned above gradually attenuates and tends to saturation around room temperature. This behavior could be ascribed to the ``bottleneck'' effect due to coupling of local moments and itinerant electrons. In addition, a Curie-Weiss-type behavior is also observed in temperature-dependent spin susceptibility. Our results strongly support the existence of local moments in these materials, while their origin is still unclear. The results also indicate strong magnetic frustration in this system, and the magnetic fluctuation mechanism for superconductivity is suggested.

Citations

• Correlated Electronic Structure ofLaO1−xFxFeAs
• Iron-based layered compound LaFeAsO is an antiferromagnetic semimetal
• Unconventional Superconductivity with a Sign Reversal in the Order Parameter ofLaFeAsO1−xFx
• Ferromagnetic spin fluctuation inLaFeAsO1−xFx
• Enhanced Orbital Degeneracy in Momentum Space for LaOFeAs
• Proximity of antiferromagnetism and superconductivity inLaFeAsO1−xFx: Effective Hamiltonian fromab initiostudies
• Crystal Structure and Antiferromagnetic Order inNdFeAsO1−xFx(x=0.0and 0.2) Superconducting Compounds from Neutron Diffraction Measurements
• Electron-Hole Symmetry and Magnetic Coupling in Antiferromagnetic LaFeAsO
• Lattice and magnetic structures of PrFeAsO,PrFeAsO0.85F0.15, andPrFeAsO0.85
• Theory of electron nematic order in LaFeAsO
• Competing orders and spin-density-wave instability in La(O 1−x F x )FeAs
• Superconductivity at 43 K in SmFeAsO1-xF x
• Minimal two-band model of the superconducting iron oxypnictides
• Theory of magnetic excitations in iron-based layered superconductors
• Different resistivity response to spin-density wave and superconductivity at 20 K in Ca1−xNaxFe2As2
• Origin of the 150-K Anomaly in LaFeAsO: Competing Antiferromagnetic Interactions, Frustration, and a Structural Phase Transition
• Superconductivity at 38 K in the Iron Arsenide(Ba1−xKx)Fe2As2