Dehydrogenation at the Fe/Lu(2)O(3) interface upon rapid thermal annealing

The interfaces between ferromagnetic electrodes and tunnel oxides play a crucial role in determining the performances of spin-based electronic devices, such as magnetic tunnel junctions. Therefore, a deep knowledge of the structure, chemical, and magnetic properties of the buried interfaces is required. We study the influence of rapid thermal annealing treatments up to 500 degrees C on the interfacial properties of the Fe/Lu(2)O(3) system. As-grown stacks reveal the presence of hydrogenated Fe-Lu-H intermetallic phases at the Fe/Lu(2)O(3) interface most likely due to the H absorption on the Lu(2)O(3) surface upon exposure to air and/or to the oxide growth. The annealing treatments induce remarkable changes of the structural, chemical, and magnetic properties at the interface, as evidenced at the atomic scale by the sub-monolayer sensitivity of conversion electron Mossbauer spectroscopy. The use of complementary techniques such as X-ray diffraction, time-of-flight secondary ion mass spectrometry, and in situ X-ray photoelectron spectroscopy, confirms that the main effect of the annealing is to gradually promote the dehydrogenation at the Fe/Lu(2)O(3) interface.