GIANT MAGNETORESISTANCE STUDIES IN (FE,CO)-AG FILMS

Giant magnetoresistance (GMR) values were meas red in thin films of Fe and Co in Ag. The best GMR results were observed in Ag-rich specimens , with maxima of 25% (30 K) and 14% (20 K) observed in Co20Ag80 and Fe 25Ag75, respectively. Magnetic data indicate a spin glasslike behavior in the as-deposited Ag-rich films. The as-made samples have a nanostr ucture, with a face centered cubic structure. Annealing of the samples over the temperature range of 200-degrees-C to 700-degrees-C led to g rain growth and subsequent phase separation of the constituent metals. A summary of the magnetic and electrical transport properties is pres ented, in relation to the crystal structure and microstructure of the TM-Ag films (TM = Fe,Co).