  First-principles calculations of electron tunneling transport in Ni and Co
break junctions reveal strong dependence of the conductance on the
magnetization direction, an effect known as tunneling anisotropic
magnetoresistance (TAMR). The origin of this phenomenon stems from resonant
states localized in the electrodes near the junction break. The energy and
broadening of these states is strongly affected by the magnetization
orientation due to spin-orbit coupling, causing TAMR to be sensitive to bias
voltage on a scale of a few mV. Our results bear a resemblance to recent
experimental data and suggest that TAMR driven by resonant states is a general
phenomenon typical for magnetic broken contacts and other experimental
geometries where a magnetic tip is used to probe electron transport.
