Challenges in the study of Fe/MgO/Fe interfaces using 3D Atom Probe

•MgO layers (4, 32 nm) between Fe layers were analysed using a laser assisted atom probe.•Varying field evaporation voltages responsible for interfacial oxide layer (bottom)•Numerical simulation used to determine the phenomena taking place at the interfaces•Lasers of wavelengths 515 nm and 343 nm were used for this study.

Detailed interface studies were conducted on two Fe/MgO/Fe systems having different thicknesses of MgO layers, using a laser assisted 3D atom probe. In conjunction with a detailed 3D reconstruction, the system exhibited an additional oxide formation at the interface between MgO and Fe of the multilayer structure. This oxide formation was found to be independent of the laser wavelength, laser fluence and the thickness of the intermediate layers. By using numerical simulations of field evaporation of two layers having two different evaporation fields, we discuss the possible oxidation mechanisms.