Tunneling anisotropic magnetoresistance on the atomic scale

Abstract

We demonstrate the occurrence of tunneling anisotropic magnetoresistance on the atomic scale using scanning tunneling microscopy (STM). Our experiments show that noncollinear atomic-scale magnetic structures can be revealed in STM using nonmagnetic tips. These observations can be explained by a variation of the local density of states of an atom depending on its magnetization direction due to spin-orbit interaction. STM simulations based on this effect are in excellent agreement with the experimental images and can explain the bias-voltage-dependent contrast found for two-dimensionally modulated spin textures.