Images of the Antiferromagnetic Structure of a NiO(100) Surface by Means of X-Ray Magnetic Linear Dichroism Spectromicroscopy

We present the first images of a surface showing clear antiferromagnetic contrast. The images were obtained for 10--80 nm thick NiO(100) films grown on Mg(100) by means of x-ray magnetic linear dichroism spectroscopy in conjunction with high resolution photoelectron emission microscopy. The surface sensitive images with a lateral resolution of better than 50 nm reveal surface line defects that exhibit antiferromagnetic order with a reduced N\'eel temperature (455 K) relative to the rest of the film surface and the bulk (523 K). Analysis of the temperature dependent images allows us to separate the spin and charge components of the linear dichroism effect.