Nanosized antiferromagnetic domains in NiO/Ag(001) films probed by polarised X-ray and unpolarised low-energy electrons

Abstract

Surface antiferromagnetism of NiO film, epitaxially deposited on Ag(001), is investigated using the absorption of linearly polarised X-ray and the diffraction of low-energy unpolarised electrons. Polarisation-dependent X-ray absorption studies reveal a preferential stabilisation of the magnetic domains with the main components of magnetic axes parallel to the interface. Furthermore, the role of interfacial strain-induced magnetocrystalline anisotropy below a critical film thickness (∼ 20 ML) could be demonstrated by the magnetic linear dichroism results. Utilising the exchange scattered electrons from various antiferromagnetic (111) planes, the magnetic twin domains could be probed by a low energy electron microscope operating in the dark-field mode. The linearly polarised X-ray, on the other hand, is sensitive to the magnetic axes orientations of Ni2+ ions and therefore, provides access to the spin domains as well as the twin domains. Comparison of results of these two independent imaging techniques demonstrates that the in-plane component of the magnetic easy axes contained by the complementary T-domains are parallel to each other.