Direct observation of spin excitation anisotropy in the paramagnetic orthorhombic state of BaFe${}_{2-x}$Ni${}_x$As${}_2$

Haoran Man, Rui Zhang, J. T. Park +4

We use transport and inelastic neutron scattering measurements to investigate single crystals of iron pnictide BaFe${}_{2-x}$Ni${}_x$As${}_2$ ($x=0,0.03$), which exhibit a tetragonal…