Surface magnetism of NiO investigated by magnetic spectromicroscopies

Antiferromagnetic (AFM) materials were not well respected from practical point of view until the discovery of interlayer exchange coupling in 1986 and giant magnetoresistance (GMR) in 1988-1989. Soon after, the old discovery (namely exchange anisotropy in 1956) and surface antiferromagnetism find their practical importance in magnetic recording, storage and sensor devices. However, the progress is partly hindered by limited experimental techniques to study surface AFM properties. This paper reviews recent experimental advances in the field of surface antiferromagnetism of prototype AFM oxide NiO(100), particularly using laterally resolved magnetic spectroscopy. Studies performed on bare NiO(100) single crystal and thin films using photoemission electron microscopy (PEEM) with X-ray magnetic linear dichroism (XMLD) as contrast mechanism and using a recently proposed approach utilizing the capability of a low energy electron microscope (LEEM), namely AFM-LEEM, are highlighted. We expect that AFM-LEEM in combination with XMLD-PEEM will soon explore more finer aspects AFM materials.