Progressive slowing down of spin fluctuations in underdoped LaFeAsO1−xFx

2013/07/11 by Franziska Hammerath, F. Hammerath, Uwe Gräfe +12 · 1 citation
Business, Management and Accounting · Materials Science · Physics and Astronomy · #Antiferromagnetism #Atmospheric temperature range #Condensed matter physics #Corporate Taxation and Avoidance #Doping #Iron-based superconductors research #Materials science #Physics #Spin (aerodynamics) #Superconductivity #Thermodynamics #Transition temperature #cond-mat.supr-con

paper · pdf · doi:10.1103/physrevb.88.104503

published as Phys. Rev. B 88, 104503 (2013) · 10 pages, 10 figures

arxiv created 2013/07/11 · openalex publication_date 2013/09/04 · arxiv updated 2013/09/05 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05

Abstract

The evolution of low-energy spin dynamics in the iron-based superconductor LaFeAsO_1\ensuremath-xF_x was studied over a broad doping, temperature, and magnetic field range (x= 0--0.15, T\ensuremath≤ 480 K, \ensuremathμ₀H\ensuremath≤ 30 T) by means of ⁷⁵As nuclear magnetic resonance. An enhanced spin-lattice relaxation rate divided by temperature (T₁T)^\ensuremath-1 in underdoped superconducting samples (x= 0.045, 0.05, and 0.075) suggests the presence of antiferromagnetic spin fluctuations, which are strongly reduced in optimally doped (x=0.10) and completely absent in overdoped (x=0.15) samples. In contrast to previous analysis, Curie-Weiss fits are shown to be insufficient to describe the data over the whole temperature range. Instead, a Bloembergen-Purcell-Pound (BPP) model is used to describe the occurrence of a peak in (T₁T)^\ensuremath-1 clearly above the superconducting transition, reflecting a progressive slowing down of the spin fluctuations down to the superconducting phase transition.

Citations

• Spin dynamics in the low-temperature tetragonal phase of≅18doped single crystalLa1.67Eu0.2Sr0.13CuO4
• Inhomogeneous Low Frequency Spin Dynamics inLa1.65Eu0.2Sr0.15CuO4
• Magnetic-field-enhanced spin freezing on the verge of charge ordering in YBa2Cu3O6.45
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• Spin Susceptibility, Phase Diagram, and Quantum Criticality in the Eelctron-Doped High Tc Superconductor Ba(Fe1-xCox)2As2
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• Upper critical field, Hall effect and magnetoresistance in the iron-based layered superconductor LaFeAsO0.9F0.1−δ

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• Enhancement of superconducting transition temperature due to antiferromagnetic spin fluctuations in iron pnictides LaFe(As1−xPx)(O1−yFy):31P-NMR studies