Thermal stability and structural ordering of thick Co2MnAl films grown on MgO and Si substrates
Abstract
While most studies on Co$2$MnAl (CMA) focus on the ultrathin regime for spintronic junctions, applications scaling with magnetic volume--such as Anomalous Nernst Effect (ANE) energy harvesters, integrated power inductors, and magnetic MEMS--require significantly thicker films. In this work, 750 nm thick CMA films were grown on MgO (001) and Si substrates to establish a roadmap for their thermal integration. Structural analysis reveals that B2 ordering is optimized on MgO at 600 ∘C, which is important for functional devices. In contrast, samples on Si substrates exhibit a disorder transition toward the A2 phase, closely linked to diffusion-driven degradation processes. Above 500 ∘C, Si interdiffusion into the Heusler layer triggers the formation of interfacial silicides and Kirkendall voids, leading to microcracking, electrical resistivity jumps, and a final fully disordered A2 phase. Despite the Mn-poor stoichiometry (Co$2.25Mn0.7Al1.05$), the films maintain a robust saturation magnetization of ~600 emu/cm3, consistent with recent theoretical models for off-stoichiometric Heusler alloys. These results define the processing windows for integrating thick CMA layers into multifunctional CMOS-compatible platforms.
Versions
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BibTeX
@misc{roblescuenca2026thermal,
title = {{Thermal stability and structural ordering of thick Co$_2$MnAl films grown on MgO and Si substrates}},
author = {David Robles-Cuenca and Juan Antonio González and Juan Pedro Andrés and Miguel Ángel Arranz and Mohamed Salaheldeen and Ricardo López Antón},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.17955},
eprint = {2610.17955},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.17955},
note = {CC BY-NC-ND 4.0},
}
RIS
TY - UNPB
TI - Thermal stability and structural ordering of thick Co_2MnAl films grown on MgO and Si substrates
AU - David Robles-Cuenca
AU - Juan Antonio González
AU - Juan Pedro Andrés
AU - Miguel Ángel Arranz
AU - Mohamed Salaheldeen
AU - Ricardo López Antón
PY - 2026
DA - 2026/10/13
PB - arXiv
DO - 10.48550/arxiv.2610.17955
UR - https://arxiv.org/abs/2610.17955
AB - While most studies on Co$2$MnAl (CMA) focus on the ultrathin regime for spintronic junctions, applications scaling with magnetic volume--such as Anomalous Nernst Effect (ANE) energy harvesters, integrated power inductors, and magnetic MEMS--require significantly thicker films. In this work, 750 nm thick CMA films were grown on MgO (001) and Si substrates to establish a roadmap for their thermal integration. Structural analysis reveals that B2 ordering is optimized on MgO at 600 ^∘C, which is important for functional devices. In contrast, samples on Si substrates exhibit a disorder transition toward the A2 phase, closely linked to diffusion-driven degradation processes. Above 500 ^∘C, Si interdiffusion into the Heusler layer triggers the formation of interfacial silicides and Kirkendall voids, leading to microcracking, electrical resistivity jumps, and a final fully disordered A2 phase. Despite the Mn-poor stoichiometry (Co$2.25Mn0.7Al1.05$), the films maintain a robust saturation magnetization of ~600 emu/cm^3, consistent with recent theoretical models for off-stoichiometric Heusler alloys. These results define the processing windows for integrating thick CMA layers into multifunctional CMOS-compatible platforms.
ER -