| With the development of electronic devices towards high frequency, miniaturization and increased integration, the materials were put forward for even higher requirements. Particularly, to meet the requirement of magnetic devices, high-frequency soft magnetic thin films, permanent thin films and giant magnetoresistance films pinned by permanent magnet become the latest hot areas of research. They are widely used in micro-inductors, micro-transformers, magnetic reading heads, electromagnetic noise suppressors and magnetic sensors. In current reasearch, the processing, structure and property relationships of the FeCo soft magntic films, the CoFe2O4 thin films and the CoNbZr/Co/Cu/Co/Sm2Fe17Nδspin valves were studied systematically.CoNbZr/FeCo and NiFe/FeCo bilayers have been fabricated. The CoNbZr and NiFe thin films serve as buffer layers. The effects of preparation conditions, such as the Ar pressure, the thickness of buffer layer and FeCo, as well as the sputtering power were investigated in the paper. The results show that both NiFe(3nm)/FeCo(40nm) and CoNbZr(2nm)/FeCo(40nm) have good soft magnetic properties.For the NiFe(3nm)/FeCo(40nm) bilayer, the coercivity of the easy axis Hce is 3.7Oe, while the coercivity of the hard axis Hch is 1.5Oe. The soft magnetic properties of CoNbZr(2nm)/FeCo(40nm) is Hce=3.9Oe, Hch=1.8Oe. The effects of oblique deposition were also studied. When the oblique angle is 30°, the in-plane magnetic anisotropy Hk changes from 20Oe to 80Oe. With further increasing the oblique angle to 60°, Hk increases to 250Oe.In order to further enhance the resistivity and the in-plane uniaxial anisotropy field of the samples, FeCoO and NiO were deposited by DC magnetron sputtering in a mixed Ar and O2 atmosphere to fabricate NiFe/FeCo/FeCoO, NiFe/FeCo/NiO multilayers. Microstrip short-circuit method was used to measure the high-frequency magnetic permeability of the samples. A high resonance frequency over 2GHz has been achieved in the multilayers, with the initial permeability over 400. In contrast to FeCo bilayers, Hk of multilayers only increased a little bit, and the measured resistivity was ～170μΩ·cm.CoFe2O4 thin films have been prepared by an electrodepositing method and magnetron sputtering for comparison. For the CoFe2O4 thin films prepared by electrodeposition, the effects of the concentration of the primary salt, the saccharine, the PH value, the density of electric current on composition of plating layer and the speed of sediment were studied in details.CoFe2O4/Cu/Si(100) films with the perpendicular anisotropy were obtained after annealing at 700℃.The perpendicular and parallel coercivities were 2156Oe and 940Oe, respectively. The saturated magnetization and remanence were 310.2kA/m and 218.3kA/m, with a remanence ratio of 0.62.When the annealing temperature increased to 900℃,the largest remanence ratio about 0.78 had been achieved. For the CoFe2O4/Cu/Si(100) films prepared by magnetron sputtering, the films also have a cubic spinel structure. The perpendicular and parallel coercivities are 9000Oe and 3145Oe, respectively. The saturated magnetization and remanence are 388.2kA/m and 275.3kA/m, with a remanence ratio of 0.82.In designing of spin valve, a permanent magnet layer was selected as the pinned layer. A physical model of spin valve reading head has been developed based on this structure. In a normal spin valve, the spontaneous magnetic anglesθ1 andθ2 are difficult to solve. In our spin valve configuration, the permanent magnetic film was used to pin one of the magnetic layer. Therefore, the angles forθ1 andθ2 can be set as 0 degree or 180 degree. The Sm2Fe17Nδpermanent magnetic films were fabricated by magnetron sputtering. The relationships between the coercivity and nitrogenization temperature have been studied. When it was used in CoNbZr/Co/Cu/Co/Sm2Fe17Hδspin vale, the 10μm×18μm spin valve elements possessed stable and non-hysteresis linear response to the rapidly changing magnetic field. Therefore, it is suitable for the applications such as magnetic sensor and magnetic reading heads...
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