Bibliographic Details
| Title: |
Formation of Mn-rich interfacial phases in Co2FexMn1-xSi thin films |
| Authors: |
Law, Ka Ming, Thind, Arashdeep S., Pendharkar, Mihir, Patel, Sahil J., Phillips, Joshua J., Palmstrom, Chris J., Gazquez, Jaume, Borisevich, Albina, Mishra, Rohan, Hauser, Adam J. |
| Publication Year: |
2023 |
| Collection: |
Condensed Matter |
| Subject Terms: |
Condensed Matter - Materials Science |
| More Details: |
We report the formation of Mn-rich regions at the interface of Co2FexMn1-xSi thin films grown on GaAs substrates by molecular beam epitaxy (MBE). Scanning transmission electron microscopy (STEM) with electron energy loss (EEL) spectrum imaging reveals that each interfacial region: (1) is 1-2 nm wide, (2) occurs irrespective of the Fe/Mn composition ratio and in both Co-rich and Co-poor films, and (3) displaces both Co and Fe indiscriminately. We also observe a Mn-depleted region in each film directly above each Mn-rich interfacial layer, roughly 3 nm in width in the x = 0 and x = 0.3 films, and 1 nm in the x = 0.7 (less Mn) film. We posit that growth energetics favor Mn diffusion to the interface even when there is no significant Ga interdiffusion into the epitaxial film. Element-specific X-ray magnetic circular dichroism (XMCD) measurements show larger Co, Fe, and Mn orbital to spin magnetic moment ratios compared to bulk values across the Co2FexMn1-xSi compositional range. The values lie between reported values for pure bulk and nanostructured Co, Fe, and Mn materials, corroborating the non-uniform, layered nature of the material on the nanoscale. Finally, SQUID magnetometry demonstrates that the films deviate from the Slater-Pauling rule for uniform films of both the expected and the measured composition. The results inform a need for care and increased scrutiny when forming Mn-based magnetic thin films on III-V semiconductors like GaAs, particularly when films are on the order of 5 nm or when interface composition is critical to spin transport or other device applications. |
| Document Type: |
Working Paper |
| DOI: |
10.1016/j.jmmm.2024.171884 |
| Access URL: |
http://arxiv.org/abs/2312.15562 |
| Accession Number: |
edsarx.2312.15562 |
| Database: |
arXiv |
