The Electrochemical Preparation,Characterization And Magnetic Property Study Of Nano Magnetic Films

A series of [Co(1.5nm)/Cu(t)]100(0.9nm0.40 can be explained by the percolation mechanism. The XRD result showed that the as-deposited films form metastable alloy structure and has the predominant orientation of (111) crystal plane in the studied Co concentration range. The orientation factor of (111) crystal plane reached maximum for the Co20Cu80 film. The fcc lattice parameterαof the single phase fcc alloy changed linearly with Co concentration. The plane distance and lattice parameter increased with annealing temperature. The diffraction peak of pure Co was first observed in the XRD spectrum of 600℃ annealed sample. The (111) and (200) peaks split into diffraction peak of pure Cu and pure Co in the diffractogram of the 700℃annealed sample, indicating phase separation occurred upon annealing. The structure of the 700℃ annealed Co20Cu80 film was characterized by TEM: the SAED result was found to be diffraction rings. The magnetic Co particles was found in the dark-field image and its in the range 5-20nm. The hysteresis loop of the as-deposited sample was close to superparamagnetic material. The value of coercivity(Hc), remanent magnetization(Mr), saturation magnetization(Ms) increased with annealing, indicating the change from superparamagnetic to ferromagnetic contribution to the GMR effect. The calculation result of magnetization also verified this change.