A series of 150 nm thick Ag100-xCox films (x varying from 12 at.% to 4
6 at.%) were grown by e-beam coevaporation in an UHV system at substra
te temperatures, T-s, between 30 degrees C and 200 degrees C, followed
by a heat treatment, For the analysis of the magnetic properties of t
he Co precipitates we fit our m(B) measurements with a log-normal dist
ribution of radii using the Langevin function to obtain mean radii of
the superparamagnetic particles. By annealing it is possible to optimi
ze the giant magnetoresistance Delta rho/rho of samples grown at room
temperature, whereas no heat treatment seems to be necessary for sampl
es evaporated at elevated temperatures. These magnetic film properties
are compared with the corresponding Co particle sizes and size distri
butions. The film structure and morphology was determined ex situ by X
-ray diffraction. Our results of the magnetic film properties an consi
stent with the observed changes in microstructure and Co particle grow
th.