Competing Explanations for Spin Wave Resonances in L10(001) FePd Thin Films with Perpendicular Magnetic Anisotropy

Published

December 2, 2025

Author(s)

Dingbin Huang, Jenae Shoup, Aaron Johnston-Peck, Deyuan Lyu, Jian-Ping Wang, Xiaojia Wang, Daniel Gopman

Abstract

The Heisenberg exchange constant plays a crucial role in determining the switching behavior of magnetic nano-objects, along with the magnetic anisotropy, saturation magnetization, and Gilbert damping. This work seeks to estimate the exchange stiffness from a thickness series of L10-ordered FePd thin films with perpendicular magnetic anisotropy. Epitaxial stresses from the buffer layers yield a substantial depth-dependent magnetoelastic anisotropy gradient within the films, which break from established magnetic spin wave resonance dispersion relationships. By combining spin wave resonance measurements on a 112-GHz ferromagnetic resonance spectrometer with micromagnetic simulations that account for the microstructural variation, this letter bridges the gap between the observed spin wave resonance dispersion and existing models. The exchange stiffness is estimated to be (8.1 ± 0.2) pJ/m, promising for high-density magnetic random-access memory with thermally stable bit cells down to 10 nm in diameter and 5 nm in thickness.

Citation

Physical Review Letters

Pub Type

Journals

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Keywords

MRAM, perpendicular magnetic anisotropy, Heisenberg exchange, ferromagnetic resonance, FMR, spin waves

Citation

Huang, D. , Shoup, J. , Johnston-Peck, A. , Lyu, D. , Wang, J. , Wang, X. and Gopman, D. (2025), Competing Explanations for Spin Wave Resonances in L10(001) FePd Thin Films with Perpendicular Magnetic Anisotropy, Physical Review Letters, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=958899 (Accessed December 14, 2025)