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The epitaxial structures of GaN films grown on AlN/Al heterostructures by pulsed laser deposition (PLD) are designed with and without an amorphous AlN layer, and quality-enhanced crack-free GaN epitaxial films are obtained.

The magnetization dynamics of an yttrium iron garnet (YIG)/Au/YIG magnon valve was investigated using broadband ferromagnetic resonance. The material characterizations of YIG/Au/YIG were performed using cross-sectional scanning transmission electron microscopy, x-ray diffraction spectroscopy, x-ray photoemission spectroscopy, Raman spectroscopy, and UV–visible spectroscopy. Asymmetric Fano resonance in the YIG/Au (60 nm)/YIG magnon valve structure was observed experimentally, and the two coupled oscillators model was used to describe the source of the Fano resonance qualitatively. We also provide a quantitative description of the Fano resonance and extract the Fano factor, which is an important feature that can be used to define the interaction sign. This represents the first attempt to apply the Fano resonance to magnetization dynamics. The spin wave resonance modes excited by the Au nanoparticles (NPs) surface plasmons were also observed in a YIG/Au NPs/YIG structure. Our findings confirm the occurrence of magnetic Fano resonance in the YIG/Au/YIG magnon valve and pave the way toward the development of quantum information devices based on magnon valves.

With the development of spintronics, garnet films with perpendicular magnetic anisotropy (PMA) have been attracting the attention of researchers for decades. In this work, bismuth-doped thulium iron garnet (Tm2BiFe5O12, TmBiIG) films of varying thickness having strong PMA effect were fabricated on substituted Gd3Ga5O12 (sGGG) (111) substrates using the pulsed laser deposition (PLD) technique. Crystallographic characterization and magnetic properties of TmBiIG films were investigated using high-resolution scanning transmission electron microscopy, X-ray diffraction, vibrating sample magnetometry, and broadband ferromagnetic resonance (FMR). A high perpendicular anisotropic field of H⊥ = 4,445 ± 7.5 Oe in a 10-nm-thick film and H⊥ = 4,582 ± 7.7 Oe in a 30-nm-thick film at room temperature were obtained and analyzed in detail. Surprisingly, an additional spin-wave mode was observed in the in-plane FMR spectra. The discrepancy between in-plane and the out-of-plane Landé g-factors established a correlation with the PMA effect in the TmBiIG films. The Landé g-factor of the TmBiIG films is much lower than that of free electrons, indicating that the strong spin–orbit coupling is caused by Tm and Bi heavy elements. The Gilbert damping factor α changed from 0.007 to 0.012 in various thicknesses of TmBiIG films.