Multiscale Symmetry Breaking Enables Tunable Magnetic Anisotropy and Damping in Co 2 FeAl Thin Films

Abstract

ABSTRACT The ability to simultaneously engineer magnetic stability and spin dissipation remains difficult to realize in scalable metallic thin films. Here, we show that multiscale symmetry breaking provides a route to achieve this control in polycrystalline Co 2 FeAl films without epitaxy, compositional complexity, or heavy‐metal incorporation. By combining nanoscale ripple templating, oblique‐angle deposition (OAD), and mechanical strain, we create a magnetic architecture composed of conformally tilted nanocolumns embedded within a strain‐biased energy landscape. This cooperative design generates a robust and tunable in‐plane uniaxial magnetic anisotropy (UMA), with the anisotropy field increasing from ≈20 Oe in the isotropic reference film to ≈250 Oe (∼1200%) in the OAD‐ripple template film and further to ≈360 Oe (1700%) under strain, while simultaneously driving a threefold enhancement of the effective damping. Correlative structural, spectroscopic, and magnetic measurements reveal physically distinct, dominant microscopic mechanisms driving UMA and damping: anisotropy is governed primarily by ripple‐directed shape anisotropy and magnetoelastic energy, whereas damping is enhanced by nanocolumnar structure and strain‐induced orbital‐moment unquenching leading to strengthened spin–orbit coupling. This work establishes nanoscale morphology and mechanical deformation as tunable design parameters for adaptive spintronics, flexible microwave technologies, and strain‐tunable magnonics.