Depth-resolved magnetization profile of MgO/CoFeB/W perpendicular half magnetic tunnel junctions
Soft X-ray resonant magnetic reflectivity allows us to probe buried magnetic interfaces of ultra-thin films by combining the depth-resolved information of X-ray reflectivity with the species selectivity of X-ray magnetic circular dichroism. It was used to study the out-of-plane (OOP) magnetization profile of a 1.4 nm thick Co8Fe72B20 layer in MgO/CoFeB/W/Ta half magnetic tunnel junctions exhibiting perpendicular magnetic anisotropy after annealing at 400°C. Sensitivity to OOP magnetization occurs at large angles, accessible thanks to the soft X-ray wavelength. Analysis of the splitting of the angle-dependent specular reflectivity curves, measured in the vicinity of the Fe and Co L3 absorption edge for circular right and left polarized incident photons, reveals a graded magnetic distribution for both elements.
V. Bansal, J.-M. Tonnerre, E. Mossang, L. Ortega, F. Fettar, et al.
