Effect Of Heat Treatment And Electron Beam Irradiation Process On Magnetic Properties Of Iron-based Amorphous Alloy Films

The soft magnetic thin films have an important position in the electronic information technology.However,amorphous alloy films prepared by pulsed laser deposition techniques have worse magnetic properties than striped amorphous samples of the same composition.In this paper,Fe-B-Si-Nb amorphous thin film was prepared on Si(100)substrate by pulsed laser deposition.The surface morphology and thickness of the films were analyzed by scanning electron microscopy(SEM).The structure of the films was analyzed by X-ray diffraction(XRD).The topography of the films were analyzed by atomic force microscopy(AFM),the magnetic properties of the films were analyzed by using the VSM components in the PPMS.The deposition parameters,heat treatment and electron beam irradiation on the structure and magnetic properties of the films were investigated.The main findings are as follows:(1)For Fe-based thin films deposited at room temperature,the films exhibits an amorphous state,the deposition rate of the film gradually decreases with increasing film thickness.The roughness of the film increases with the increase of the thickness.The coercivity of the film increases with the thickness of the film.(2)The increases of substrate temperature will cause a decline in the quality of the film.There are many holes in the surface of the film,and the pore size increases with increasing deposition temperature.Roughness of the film also increases with deposition temperature,the coercivity increases as the film deposition temperature will rise after the first drop,until the soft magnetic properties deteriorate.(3)After the Fe-based amorphous alloy films annealed at 500℃ for 1 hour,the crystalline α-Fe and crystalline Fe3 Si phases appeared on the XRD image,the grain sizes of the crystalline phase were 34 nm and 30 nm,respectively.The roughness of the film increases as the annealing temperature increases.The coercivity of the film is the lowest when the annealing temperature is 300 ° C,and the coercivity of the film decrease by 43% compared to the as-deposited film.(4)When annealed at 300℃,the roughness of the film will increase with the annealing time,however,the films are still amorphous state.The coercivity of the film will decrease first and then rise with the annealing time,the coercivity of the film decreased by 73% when annealed at 300 ℃ for 0.5 h.(5)A lot of flower-like structures appears on the film surface when irradiated with electron beam.The number of the flower-like structure will increase with the increase of irradiation dose.The irradiated thin films were still amorphous.The magnetic properties of the films after irradiation showed that the electron beam irradiation has a positive effect on the decrease of coercivity of the film.When the electron beam irradiation dose is 40 k Gy,the coercivity of the film is 5.4Oe,and the coercivity of the film is reduced by 89% compared with the original film.(6)Comparing the method of Annealing and Electron Beam Irradiation we found that: The electron irradiation method is more effective than the annealing method in reducing the coercivity of the film.