Multiferroic heterostructures, which integrate individual ferroelectric (FE) and ferromagnetic (FM) materials, allow to control and modify
the ferromagnetic properties through the application of an electric field. In the last years, antiferromagnetic (AFM) thin films have been gaining increasing attention as an alternative from FM layers in multiferroic heterostuctures, with potential improvements in low-power and high data robustness performances for magnetic random access memories.
Our work is focused on the chemical and magnetic properties of such AFM/FE heterostructure, considering FeMn as the AFM layer and PMN-PT as FE substrate. Thin films of 4 nm thickness of FexMn1-x, with composition in the range 0.7<x<1, have been deposited by Molecular Beam Epitaxyon different substrates, namely SrTiO3 (STO) and PMN-PT, the first one used as a reference non-ferroelectric substrate. The ratio x is selected in the range where the AFM/FM transition takes place for bulk FeMn.
We will discuss the effects of different polarization states of the PMN-PT on the AFM/FM transition, by means of x-ray absorption spectroscopy (XAS) and x-ray magnetic circular dichroism (XMCD) at Fe and Mn L2,3 edges, and Magneto-Optic Kerr effect (MOKE).