Static and Dynamic Magnetism in Underdoped Superconductor BaFe 1.92 Co 0.08 As 2
2009; American Physical Society; Volume: 103; Issue: 8 Linguagem: Inglês
10.1103/physrevlett.103.087002
ISSN1092-0145
AutoresA. D. Christianson, M. D. Lumsden, S. E. Nagler, G. J. MacDougall, Michael A. McGuire, Athena S. Sefat, Rongying Jin, B. C. Sales, David Mandrus,
Tópico(s)Physics of Superconductivity and Magnetism
ResumoWe report neutron scattering measurements on single crystals of BaFe$_{1.92}$Co$_{0.08}$As$_2$. The magnetic Bragg peak intensity is reduced by 6 % upon cooling through T$_C$. The spin dynamics exhibit a gap of 8 meV with anisotropic three-dimensional (3d) interactions. Below T$_C$ additional intensity appears at an energy of $\sim$4.5(0.5) meV similar to previous observations of a spin resonance in other Fe-based superconductors. No further gapping of the spin excitations is observed below T$_C$ for energies down to 2 meV. These observations suggest the redistribution of spectral weight from the magnetic Bragg position to a spin resonance demonstrating the direct competition between static magnetic order and superconductivity.
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