Publication Type
Journal
Journal Name
Physical Review B
Publication Date
Page Number
012502
Volume
80
Issue
1
Abstract
Superconductivity appears to compete against the spin density wave
in Fe pnictides. But the optimally doped samples show a quasitwodimensional
spin excitation centered at the (0.5, 0.5, L) wavevector, �the spin resonance peak�, that is strongly tied to the onset of superconductivity. By inelastic neutron scattering on single crystals we show the similarities and differences of the spin excitations in BaFe1.84Co0.16As2,with respect to the spin excitations in the cuprates that exhibit hightemperature superconductivity. Unlike in the cuprates the resonance peak in this compound is
asymmetric in energy, but as in the cuprates the resonance occurs as an enhancement to a part of the spin excitation spectrum which extends to higher energy and higher temperature.
PACS # 74.70.b,
74.20.Mn, 78.70.Nx, 74.25.Ha
