In order to achieve higher signal-to-noise (S/N) ratio in perpendicular recording media, highly oriented perpendicular magnetic recording layers with relatively high perpendicular coercivity H c, small-grained films, and large perpendicular squareness ( S ⊥ = Mr ⊥/ Ms ⊥) are required. For high-density perpendicular magnetic recording (PMR), the media should possess a chemical stability, mechanical durability, moderate hard magnetic properties, and small grains. Those interested in magnetic recording have focused on the preparation of c-axis magnetic layers with thickness typically ranging from a few tens of nm to 200 nm as potential perpendicular recording media. Workers interested in microwave applications have emphasized epitaxial growth of thick (several µm), c-axis oriented, nearly single-crystal films for the construction of microwave filters and other devices. Hexagonal barium ferrite with magnetoplumbite structure, i.e., BaF 12O 19, is an important material for applications involving high-density perpendicular as well as longitudinal magnetic recording media, spintronic devices, microwave circuits, and microwave-assisted magnetic recording (MAMR) because of the recorded large uniaxial magnetic anisotropy H A, relatively high permeability and low conduction losses. These methods comprise high-resolution X-ray diffraction, atomic force microscopy, high-resolution transmission electron microscopy (TEM), scanning TEM combined with energy-dispersive X-ray spectroscopy, and vibrating sample magnetometer. For a deep understanding of the effect of laser fluence on the microstructure, chemical composition, and on the magnetic properties of thin BaM films, the results of complementary methods are combined. We found that both the lateral coherent block size and misorientation of mosaic blocks are remarkably affected by the growth kinetics, which itself depends on the energy per pulse. In turn, this has contributed to the enhancement of the coercive field from H c = 1769 Oe to H c = 2166 Oe as it is required for the improvement of perpendicular recording resolution. However, we also concluded that the increase of fluence leads to the formation of a non-stoichiometric BaM film through two nucleation steps and an output growth of small grains in addition to the increase of the defect density. We demonstrated that the microstructure, morphology, and stoichiometry of the hexaferrite BaFe 12O 19 films can be affected by raising the corresponding energy per pulse from 25 to 75 mJ. High-quality BaFe 12O 19 (BaM) films with high uniaxial anisotropy fields of H A = 17.5 and 18.5 kOe were obtained by pulsed laser deposition (PLD) at two fluences of 1.5 and 5.1 J/cm 2 on YSZ(111) substrate, using a platinum interlayer for reducing lattice mismatch.
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