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arXiv · 1501.07360

Interface observation of heat-treated Co/Mo2C multilayers

Yanyan Yuan·Karine Le Guen·Jean-Michel André·Christian Mény·Corinne Ulhaq·Anouk Galtayries·Jingtao Zhu·Zhanshan Wang·Philippe Jonnard
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Abstract

We study the interface evolution of a series of periodic Co/Mo2C multilayers as a function of the annealing temperature up to 600{\textdegree}C. Different complementary techniques are implemented to get information on the phenomenon taking place at the interfaces of the stack. The periodical structure of Co/Mo2C multilayer is proven by Time-of-flight secondary ion mass spectrometry (ToF-SIMS) depth profiles which demonstrate the formation of an oxide layer at both air/stack and stack/substrate interfaces. From Nuclear magnetic resonance (NMR) spectra, we observed the intermixing phenomenon of Co and C atoms for the as-deposited sample, and then at annealing temperature above 300{\textdegree}C Co and C atoms separate from their mixed regions. Comparison of NMR results between Co/Mo 2 C and Co/C references confirms this phenomenon. This is in agreement with x-ray emission spectroscopy (XES) measurements. Furthermore the calculation of the Co-C, Co-Mo and Mo-C mixing enthalpy using Miedema's model gives a proof of the demixing of Co and C atoms present within the stacks above 300{\textdegree}C. From the transmission electron microscopy (TEM) analysis, we found the presence of some crystallites within the as-deposited sample as well as the mainly amorphous nature of all layers. This is confirmed using x-ray diffraction (XRD) patterns which also demonstrate the growth of crystallites induced upon annealing.

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Yanyan Yuan, Karine Le Guen, Jean-Michel André, Christian Mény, Corinne Ulhaq, Anouk Galtayries, Jingtao Zhu, Zhanshan Wang, Philippe Jonnard. 2015-01-29. Interface observation of heat-treated Co/Mo2C multilayers. https://doi.org/10.1016/j.apsusc.2014.12.055

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