|
M-type hexagonal barium ferrite material BaFe12O19 (BAM) due to having a high resistivity, a large high-frequency permeability, strong uniaxial magnetic anisotropy and the stability of the physical and chemical properties and other characteristics much attention, it monolithic microwave integrated circuit (MMIC), high-density perpendicular magnetic recording media, such as a wide range of applications. The realization of these applications are required to obtain good crystallinity, highly c-axis oriented, remanent magnetization than the big (MS / Mr. GT; 0.9) of barium ferrite thick film (gt; 10μm). However, the preparation of such a thick film in the actual process and theoretical studies have certain difficulties. This thesis from research BaM film on the sapphire substrate c-axis growth process, the use of X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), vibrating sample magnetometer (VSM) characterized structure, morphology, magnetic energy, obtained the law of the process parameters and the macroscopic magnetic microscopic growth process. Then developed a heat treatment of a set of optimized conditions, crystalline BAM seed layer, layer by layer growth, \The same time, the use of TiN, MgO thin layer alternative crystallization BAM seed layer, and systematic study of the use of \Finally, drawing on the experimental results, a preliminary study of the integrated growth of barium ferrite materials with wide band gap semiconductor GaN \Therefore, the paper obtained the following conclusions: (1) In the below 750oC, the in situ deposition of barium ferrite films showed an amorphous state, and only weak MH hysteresis loop; study by the after bit annealing process conditions to obtain an optimized set of annealing conditions: (1) atmospheric oxygen pressure 1000oC annealing 1 hour to prepare a good crystallinity, the height c of the orientation, has a certain magnetic properties (the saturation magnetization of 3000 G, the remanence ratio of 0.6) the barium ferrite seed layer; (2) crystalline BAM for the seed layer, thick-film barium ferrite was prepared by layer by layer growth mode, access to grow on the seed layer thickness of 2μm C orientation, saturation magnetization The 3500G, remanence ratio barium ferrite thick film of about 0.65. When the film thickness is increased further to 3.4μm, the sample surface pores, cracks, hindered improved thick film of barium ferrite magnetic. (3) Select TiN, MgO thin layer alternative crystallization seed layer, obtained in the buffer barium ferrite thick film of MgO thin layer having the highest saturation magnetization to 4006 G, a remanence ratio of 0.7. (4) successfully passing through MgO thin layer on the GaN epitaxial films prepared barium ferrite film, the maximum saturation magnetization of 3208 G, and the remanence ratio of 0.7.
|