Preparation Of FeCo - Based Soft Magnetic Film And Its Microwave Soft Magnetic Properties

The rapid development of today’s electronic information industry, especially the development of modern electronic devices and data transmission technology, the electronic devices and materials as the basis of the electronic components are also put forward higher request, this will require a soft magnetism and high frequency characteristics of magnetic thin films are studied and improved. For example, the vertical magnetic recording head and thin film magnetic inductor, require corresponding soft magnetic thin films have the following characteristics, including high saturation magnetization, good high frequency response, and low coercive force. In order to obtain good ferromagnetic thin films, this thesis conducted from FeCoAlO high-frequency magnetic thin film preparation, performance testing to the experimental results of discussion and so on a series of work, to explore the high frequency properties of ferromagnetic thin film materials. The specific research work mainly include:(1) In this thesis, a great enhancement of ferromagnetic resonance fFMR from 3.4 GHz to 9.6 GHz was obtained in FeCoAlO/PZN-PT composite by two step enhancement: in the first step, the ferromagnetic resonance frequency fFMR increases from 3.4 GHz to 5.5 GHz at Si substrate due to the variation of residual stress induced by the gradient compositions of Al and O atoms; And in the second step, the fFMR dramatically increases from 5.4 GHz to 9.6 GHz at PZN-PT substrate due to the magnetoelectric coupling(MEC) effect via applied electric field. The dramatic enhancement of f FMR can be attributed to the increase of uniaxial magnetic anisotropy field HK from 100 Oe to 735 Oe due to the CGS and the ME coupling. This superposition method showed big advantage over any of the single method, therefore was a promising method for preparing high-performance microwave SMFs with fFMR in excess of X-band.(2) The nanocrystalline Fe Co AlO films with a macro vortex magnetic anisotropy were prepared by composition gradient sputtering method. Owing to the competition between the stresses along radial and the tangential directions, the residual stress from tensile stress to compressive one from one side to the other. As a result, the easy axis of the FeCo AlO films is gradually rotated from radial direction to the tangential one, and a macro vortex magnetic anisotropy was formed. The vortex CGS method showed good high-frequency ferromagnetic performances, such as, high permeability of about 100, cut-off frequency in 2 GHz and Qm factor more than 50.