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NiCuZn soft ferrite resistivity, eddy current loss is small, low cost, its frequency range kHz to nearly GHz, the wider than MnZn (1MHz) and the following NiZn (1-100MHz) ferrite materials, can be achieved transmission of high frequency RF signal energy and impedance conversion, widely used in the computer, television, communications and other fields, mainly used in the manufacture of inductors and other components, but so far, successfully used in integrated circuits the high frequency NiCuZn soft magnetic ferrite thin films also less preparation and research, the success of the preparation of a high saturation magnetization, the low coercivity NiCuZn ferrite thin films become an important limiting factor for its future application. In the process of the preparation of thin film materials, sputtering, vacuum evaporation process. But the sputtering method, the preparation of thin-film process is the ion sputtering rate caused by different constituent segregation and low deposition rate drawback, vacuum evaporation is also the presence of poor reproducibility and poor adhesion drawback, and the ferrite of high melting point such that a particular embodiment of a vacuum evaporation process difficult. Common method - sol - gel spin coating ferrite thin films prepared reports prepared another film, however, is still relatively small. Sol - gel process because it allows the reactants to achieve the mixing of the molecular level, easy control of composition, effective reduction of the sintering temperature, etc., are widely used in the field of materials science and ceramic technology. The gel can be applied to the spin coating method on the substrate film, and its advantages as the conditions are simple and independent of the limitations of the object shape. This paper, the sol - gel spin coating process of the the NiCuZn soft ferrite powder and films prepared, using N, N-dimethyl formamide as a solvent, polyvinylpyrrolidone as a surface active agent, study the composition ratio, The nature of the sol-gel process conditions, the impact of the powder and thin-film magnetic in the preparation of the magnetic properties of excellent NiCuZn soft ferrite powder material film do actively exploring and get some meaningful results. 1. Stable gel at ambient temperature self-propagating combustion, the resulting precursor powder in the ≥ 750 ° C under the processing, and will generate a relatively pure spinel phase. The corresponding constituent of the thin film at 400 ℃ for a long time heat treatment, no spinel phase formation, when the heat treatment temperature reaches about 600 ℃, i.e. able to generate completely spinel phase. 2. A powder using appropriate iron deficiency formulations Ni0.4Cu0.2Zn0.4Fe1.9O4 obtained, at 900 ℃ incubated for three hours, the coercive force of up to 90E, a saturation magnetization of 72.4 emu / g, continue l high temperature, when the temperature reaches 1000 ° C, the coercive force of the this case the sample to 50e, and the saturation magnetization of 73.57 emu / g. 3 compared with the non-acetate was added to the sol, adding an appropriate amount of acetic acid pH adjusted value of 3.2, the smaller the coercive force of the thin film on the Si substrate obtained samples, the higher activity of the visible adding acid gel obtained. 4 sol aged at different temperatures, the sample coercive force Hc with the sol aging placement time is gradually reduced, and then stabilized, wherein the smaller the coercive force of the sample placed at room temperature, sol obtained and the first stable. 5 In order to obtain a high performance thin film sample, it should be used Ni0.4Cu0.2Zn0.4Fe2O4 positive ratio recipe advantageous sintering process is between 500 ° C -650 ° C, and incubated for a short time, to suppress the grain growth , wherein the treatment temperature is 585 ° C and the sample, the coercive force reaches 160e, at a higher temperature, the coercive force and the saturation magnetization will increase, the saturation magnetization at a higher temperature can reach 300 emu/cm3. 6 measurements at higher temperatures treated powder and the film, measured by electron spin resonance spectrum spectrum will change, the point of intersection of the curve with the abscissa reflects the change of the value of g, means that the ions between placeholder change . This may be associated with the application of sol - gel ions with very high activity, the appropriate temperature will cause the evaporation of Zn element, resulting spinel ferrite A bit missing Zn ions will be substituted by other ions concerned.
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