Alberto Brambilla: Low-dimensional antiferromagnetic transition metal oxides coupled to ferromagnetic Fe(001) films

Intriguing magnetic properties can be obtained in systems containing antiferromagnetic (AF) transition metal oxides both by low-dimensionality and by proximity to ferromagnetic (F) layers, giving rise to well-known exchange coupling phenomena. The comprehension and the possible application of such properties must pass through a sound understanding of the correlations between their magnetic, chemical, structural and morphologic features. So far, we have collected a rich record of investigations on AF/Fe layered structures. Several issues, such as chemical interactions at the interfaces, magnetic couplings in AF/Fe and Fe/AF/Fe systems, spin reorientation transitions, development of nanometer sized domains and very sharp domain walls, have been investigated. We are currently pursuing new efforts towards the nanoscale understanding of AF/F structures by studying the early stages of formation of oxide nanostructures coupled to Fe substrates. Such systems contain appealing ingredients, such as high chemical reactivity, stabilization of unusual stoichiometries, presence of metastable phases. This talk will focus on Scanning Tunneling Microscopy/Spectroscopy investigations of transition metal oxides nanostructures based on Co, Ni and Cr. Such investigations are supported by electron spectroscopies – also with spin resolution – by x-ray magnetic dichroism and magneto-optical Kerr effect measurements.

The results will be discussed in the perspective of a comparative study aimed to identify the key features to develop new nanostructured magnetic structures with a bottom-up approach.