Nanoscale Ga/Al substituted yttrium iron garnet films by liquid phase epitaxy

作者：Yuanjing Zhang, Qiang Xue, Feng Wang, Li Han, Ming-Jia Li, Shuting Yang, Yingli Liu, Aimin Hu, Lichuan Jin, Qiye Wen, Huaiwu Zhang, Qinghui Yang · 发表于：AIP Advances · 年份：2024 · DOI：10.1063/5.0233442 · 被引用次数：4 · 研究领域：Magneto-Optical Properties and Applications、Photorefractive and Nonlinear Optics、Magnetic properties of thin films

Yttrium iron garnet (YIG) has minimum damping factor and low ferromagnetic resonance (FMR) linewidth, making it a preferred material for low loss microwave and spintronic devices. The saturation magnetization of YIG is 1750 Gauss, and for low-frequency devices, a lower saturation magnetization is more suitable. Ga3+ and Al3+ are with smaller radii and non-magnetic moment, so the substitution of Ga3+ and Al3+ can decrease saturation magnetization. Here, 4.8–193.7 nm ultra-thin Y3(GaAlFe)5O12 garnet (GaAl-YIG) monocrystalline films are prepared on gadolinium gallium garnet (GGG) substrates by using the liquid-phase epitaxy (LPE) method. As expected, these films exhibit a low saturation magnetization of almost less than 100 Gauss, while their FMR linewidth remains at levels close to that of YIG. The films show a (111) orientation and in a state of tension, and the diffraction intensity of the films get stronger as films thickness increases. The free energy and density of states are calculated for different Ga/Al substitution position by density functional theory simulations. The elements show a different diffusion distance in the GaAl-YIG/GGG interface, and the variation of magnetization properties with interface width are analyzed. The surface roughness of the films is only a few angstroms. The damping factor of these ultra-thin films are on an order of 10−4 except the 4.8 nm film, which suggests that the minimum thickness of the garnet film with good performance by using the L...