抄録
The influence of impurities in the sputtering atmosphere on the microstmcture and giant magnetoresistance (GMR) of Ag100-xCox (x = 0-62 at%) thin films was investigated Ag-Co films were prepared on quartz substrates at room temperature, varying the purity of the sputtering atmosphere by changing the base pressure, with 10-11 Torr for an extremely clean process (XC-process) and 10-7 Torr for a lower-grade process (LG-process). The correlation between the microstructure and the GMR of Ag-Co films after annealing is discussed It was found that (1) the precipitation of Co particles progressed in the as-deposited films, and the degree of supersaturantion of the matrix phase in the LG-processed films was higher than that in the XC-processed films; (2) the size of the Co particles precipitated in the as-deposited LG-processed films was larger than that in the XC-processed films, and resulted in a higher MR ratio of the as-deposited LG-processed films than that of the XC-processed ones under a maximum applied field of 14 kOe; (3) the magnitude of the MR ratio in the XC-processed films after annealing above 300°C was larger than that in the LG-processed ones, apparently because of the homogeneity of the Co particles of the precipitate.
