Temperature dependent intrinsic Gilbert damping in magnetostrictive FeCoSiB thin film

A low Gilbert damping factor is crucial for emerging magneto-acoustic devices. In current work, angle-dependent and temperature-dependent Gilbert damping of magnetostrictive FeCoSiB thin films have been investigated using electron spin resonance (ESR) and vector network analyzer ferromagnetic resonance (VNA-FMR) techniques, respectively. A very low Gilbert damping factor similar to 0.0038 was measured with in-plane magnetic fields at room temperature. Temperature-dependent VNA-FMR results between 10 K and 300 K exhibit a conductivity-like damping feature, which can be attributed to the spin-orbital coupling dominantly controlled by the intraband scattering. Our results clearly indicate that highly magnetostrictive or piezomagnetic film does not necessarily have a high intrinsic damping factor.