Spin-polarized scanning tunneling spectroscopy of dislocation lines in Fe films on W(1 1 0)

We have studied the spin-resolved electronic properties of dislocation lines on the Fe double-layer (DL) on W(1 1 0) by spin-polarized scanning tunneling spectroscopy. The data reveal that the dislocation lines are ferromagnetically ordered with the magnetic contrast exhibiting a pronounced bias-dependence. By comparing tunneling spectra which were measured on the pseudomorphic DL and at different lateral separation from the dislocation line, we find a pronounced shift of a peak which originally appears at positive sample bias towards the Fermi level EFEF. In contrast, the binding energy of a peak just below EFEF remains constant but increases in intensity. This causes a pronounced modification of the bias voltage-dependent magnetic asymmetry.