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

TY - JOUR

T1 - Substrate dependent reduction of Gilbert damping in annealed Heusler alloy thin films grown on group IV semiconductors

AU - Love, C. J.

AU - Kuerbanjiang, B.

AU - Kerrigan, A.

AU - Yamada, S.

AU - Hamaya, K.

AU - Van Der Laan, G.

AU - Lazarov, V. K.

AU - Cavill, S. A.

N1 - Funding Information: This work was partly supported by JSPS KAKENHI (Grant No. 19H05616) and EPSRC under Grant No. EP/K03278X/1. © 2021 Author(s). Uploaded in accordance with the publisher’s self-archiving policy. Further copying may not be permitted; contact the publisher for details

PY - 2021/10/25

Y1 - 2021/10/25

N2 - 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.

AB - 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.

UR - http://www.scopus.com/inward/record.url?scp=85118462660&partnerID=8YFLogxK

U2 - 10.1063/5.0060213

DO - 10.1063/5.0060213

M3 - Article

AN - SCOPUS:85118462660

SN - 0003-6951

VL - 119

JO - Applied Physics Letters

JF - Applied Physics Letters

IS - 17

M1 - 172404

ER -