FMR Study of ZnFe2O4 Thin Films in varied Growth Environments

• Published in: IEEE transactions on magnetics p. 1
• Main Authors: Singh, Nitesh, Annadi, Anil, Rastogi, Ayush, Kumar, Naresh, Sahu, Baidyanath, Bhoi, Biswanath, Bohra, Murtaza
• Format: Journal Article
• Language: English
• Published: IEEE 14.08.2024
• Subjects: Argon; Damping; FMR; Iron; Line width; Magnetic properties; Magnetomechanical effects; Negative Gilbert damping; Spintronic; X-ray scattering; Zinc
• ISSN: 0018-9464
• DOI: 10.1109/TMAG.2024.3443748

The quest for improved ferrimagnetic insulators has garnered significant research interest for spintronic devices due to their low damping constants. In this work, we investigated the growth and frequency - dependent microwave properties of sputtered ZnFe 2 O 4 thin films grown under different gaseous environments and substrate temperatures ( Ts ). While an argon environment promotes (111) textured ZnFe 2 O 4 growth at intermediate Ts , an oxygen environment produces amorphous ZnFe 2 O 4 regardless of T s . A reasonably high effective magnetization, 4π M eff =~ 0.3-3.7 kG and effective anisotropy were estimated by ferromagnetic resonance (FMR) using Kittel equations in both gaseous environments at intermediate Ts . The lowest Gilbert damping constant (α ≈ 4.18 × 10 -3 ) and inhomogeneous broadening (Δ H 0 =318 Oe) were observed at the highest T S in the argon environment. Landau-Lifshitz damping plus inhomogeneous broadening alone cannot describe the damping in all ZnFe 2 O 4 thin films; a low-field-loss effect has to be considered to describe the entire frequency dependence of the linewidth.