Coexistence of Low Damping and Strong Magnetoelastic Coupling in Epitaxial Spinel Ferrite Thin Films

Low-loss magnetization dynamics and strong magnetoelastic coupling are generally mutually exclusive properties due to opposing dependencies on spin–orbit interactions. So far, the lack of low-damping, magnetostrictive ferrite films has hindered the development of power-efficient magnetoelectric and acoustic spintronic devices. Here, magnetically soft epitaxial spinel NiZnAl-ferrite thin films with an unusually low Gilbert damping parameter (<3 × 10⁻³), as well as strong magnetoelastic coupling evidenced by a giant strain-induced anisotropy field (≈1 T) and a sizable magnetostriction coefficient (≈10 ppm), are reported. This exceptional combination of low intrinsic damping and substantial magnetostriction arises from the cation chemistry of NiZnAl-ferrite. At the same time, the coherently strained film structure suppresses extrinsic damping, enables soft magnetic behavior, and generates large easy-plane magnetoelastic anisotropy. These findings provide a foundation for a new class of low-loss, magnetoelastic thin film materials that are promising for spin-mechanical devices.

A new thin-film magnetic insulator, epitaxial spinel NiZnAl-ferrite, with low damping and substantial magnetostriction, is presented. This exceptional combination of properties is enabled by the cation chemistry and coherently strained film growth of the NiZnAl-ferrite. The findings provide a foundation for a new class of low-loss, magnetoelastic thin films that are promising for spin-mechanical devices.

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