Implantation Nifeco / Ag Granular Film Giant Magnetoresistance Effect

In this paper, the granular thin films composed of zero-magnetostriction alloy NiFeCo and non-magnet metal Ag were deposited by DC magnetron sputtering. The effect of ion implantation, annealing and various magnetic concentrations on the films were investigated. The GMR and magnetism of the films were measured by four-point probe device and Vibatinal Sample Magnetometer (VSM) respectively The structure of the films was determined by X-ray Diffiaction (XRD). The component of the films was analyzed by Rutherford Backscattering Spectroscopy (RBS). The surface image, section image and magnetic domain were observed by Field Electron Microscope (FEM), Atom Force Microscope (AFM) and Magnetic Force Microscope (MFM) respectively. The results showed that:The technique characteristic of self-designed and self-manufactured RFMS-4 sputtering apparatus with special magnet field distribution was stable and creditable. The concenlration and deposition rate of the films were stable by the optimal craft on the RFMS-4 sputtering apparatus.For the NIFeC0/Ag granular thin films without ion implantation: the optimal annealing temperature was 30(YC and the optimal magnetic concentration was 36%, and the best GMR was 5% in 300K and 19Gb in 20K(the magnetic field up to 7.6KOe).The best GMR of the film with Fe ion implantation was 2.3% and reach to 90/o after annealing (the magnetic field up to lOKOe in 300K), but the highest GMR of the film with Co ion implantation was 5.5% and reach to 9.8% after annealing. This is the highest value of the granular films made by ion implantation in the world until now.The effect of Co ion implantation was more obvious than Fe ion implantation when it was annealed at lower temperature, but their GMIR were close when annealing at higher temperature.The optimal annealing temperature was changed to 360 ~C and the optimal magnetic concentration was unchanged of the NiFeCo/Ag granular thin films after Fe ion or Co ion implantation. There existed a critical strengthen diffuse annealing temperature in the NiFeCo/Ag granular thin films with ion implantation. Strengthen diffuse effect was very obvious after the annealing temperature reached to the critical temperature, and the GMIR was greatly increased. The critical strengthen diffuse annealing temperature of NiFeCo/Ag granular thin films with Co ion implantation was 320 0C...