Determination of the magnetization profile of Co/Mg periodic multilayers by magneto-optic Kerr effect and X-ray magnetic resonant reflectivity

TL;DR

This study combines simulations and measurements of resonant magnetic reflectivity to determine the magnetization profile of Co/Mg multilayers, revealing the presence of thin magnetic dead layers at interfaces.

Contribution

It introduces a model incorporating 0.25 nm thick magnetic dead layers at Co/Mg interfaces and validates it through combined simulation and experimental measurements.

Findings

Magnetic dead layers of 0.25 nm exist at Co/Mg interfaces.

The model explains the enhanced dichroic signal near the third Bragg peak.

Interfaces are magnetically abrupt despite structural intermixing.

Abstract

The resonant magnetic reflectivity of Co/Mg multilayers around the Co L2,3 absorption edge is simulated then measured on a specifically designed sample. The dichroic signal is obtained when making the difference between the two reflectivities measured with the magnetic field applied in two opposite directions parallel to the sample surface. The simulations show that the existence of magnetic dead layers at the interfaces between the Co and Mg layers leads to an important increase of the dichroic signal measured in the vicinity of the third Bragg peak that otherwise should be negligible. The measurements are in agreement with the model introducing 0.25 nm thick dead layers. This is attributed to the Co atoms in contact with the Mg layers and thus we conclude that the Co-Mg interfaces are abrupt from the magnetic point of view.