Antiferromagnetic domains distribution carried by stoichiometry

We present a spatially resolved X-ray magnetic linear dichroism study of high quality micron-sized mixed nickel-cobalt oxide (NCO) crystals. Ni x Co 1−x O were prepared in-situ by high-temperature oxygen-assisted molecular beam epitaxy on Ru(0001) single crystal. To check the effect of incorporating Ni in the cobalt oxide films, three different composition were prepared. The element specific XMLD measurements reveal strong antiferromagnetic contrast at room temperature and magnetic domains up to one micron wide, reflecting the high structural quality of the islands. By means of vectorial magnetometry, the spin axis orientation of the domains was determined with nanometer spatial resolution, and found to depend on the stoichiometry of prepared crystals.