Magnonlike dispersion of spin resonance in Ni-doped BaFe₂As₂

M. G. Kim, G. S. Tucker, D. K. Pratt, S. Ran, A. Thaler, A. D. Christianson, K. Marty, S. Calder, A. Podlesnyak, S. L. Bud’ko, P. C. Canfield, A. Kreyssig, A. I. Goldman, and R. J. McQueeney

Accepted Friday Mar 29, 2013

Inelastic neutron scattering measurements on Ba(Fe0.963Ni0.037)2As2 manifest a neutron spin resonance in the superconducting state with anisotropic dispersion within the Fe layer. Whereas the resonance is sharply peaked at QAFM along the orthorhombic a axis, the resonance disperses upwards away from QAFM along the b axis. In contrast to the downward dispersing resonance and hour-glass shape of the spin excitations in superconducting cuprates, the resonance in electron-doped BaFe2As2 compounds possesses a magnon-like upwards dispersion.