Substrate dependent reduction of Gilbert damping in annealed Heusler alloy thin films grown on group IV semiconductors

C. J. Love, B. Kuerbanjiang, A. Kerrigan, S. Yamada, K. Hamaya, G. Van Der Laan, V. K. Lazarov, S. A. Cavill*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


A structural and FMR study is presented for epitaxial thin films of the Heusler alloy Co2FeAl0.5Si0.5 (CFAS) grown on Ge(111) and Si(111) substrates. All films, as-grown and post-annealed, show B2 ordering; full chemical order (L21) is not obtained over the range of anneal temperatures used in this study. As-grown films show a lower Gilbert damping constant, α, when grown on a Si(111) substrate compared to Ge(111). Annealing the films to 450 °C significantly reduces α for CFAS on Ge while increasing α for CFAS on Si. This is related to a substrate dependent competition between improvements in lattice structure and increased interfacial intermixing as a function of anneal temperature. The optimal annealing temperature to minimize α is found to differ by ∼100 K between the two substrates. Above an anneal temperature of 500 °C, films grown on both substrates have increased coercivity, decreased saturation magnetization, and show characteristic two-magnon scattering features.

Original languageEnglish
Article number172404
Number of pages7
JournalApplied Physics Letters
Issue number17
Publication statusPublished - 25 Oct 2021

Bibliographical note

Funding Information:
This work was partly supported by JSPS KAKENHI (Grant No. 19H05616) and EPSRC under Grant No. EP/K03278X/1.

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