Origin of high-frequency magnetic loss of Y₃Fe₅O₁₂ single crystal thin films prepared with high-throughput screening by magnetron sputtering

In this study, yttrium iron garnet (Y3Fe5O12, YIG) single crystal nanofilms were deposited at room temperature on a Gd3Ga5O12 (GGG) (111) substrate via magnetron sputtering and ex situ annealing. A high-throughput method was used to systematically study the effects of sputtering gas pressure, sputtering power, and annealing temperature on the microstructure, ferromagnetic resonance signal, and high-frequency magnetic loss. The YIG films fabricated at an Argon pressure of 3 Pa, a sputtering power of 95 W, and an annealing temperature of 800 degrees C possessed the highest saturation magnetization and lowest linewidth (13.6 Oe). Furthermore, the maximum value of permeability ( mu') was 25.54 under an applied field H-ex = 30 Oe of the YIG/GGG (111) film for the first time. In addition, the sources of the high-frequency magnetic loss in the YIG film were investigated. In detail, the roughness, thickness, and polycrystalline structure, along with the existence of oxygen vacancies and anisotropic fields, influenced the linewidth of the film. This study provides a method to prepare single-crystalline YIG films via room-temperature deposition and ex situ annealing for potential applications in high-frequency microwave devices.