CHARACTERISTIC HIGH-FIELD DEPENDENCE AND COMPOSITION VARIATION OF GIANT MAGNETORESISTANCE IN FE AG GRANULAR-MATERIALS/

Magnetoresistance (MR) measurements of Fe-cluster-dispersed Fe-Ag film s fabricated by using the ion-cluster-beam technique display the follo wing features. (1) The giant magnetoresistance (GMR) effect is observe d in the Fe/Ag granular alloys with 12 to 45 at.% Fe, whereas it is su ppressed in the Fe-rich region. (2) The MR curves display both saturat ion- and nonsaturation-type behavior even in a high magnetic field of 140 kOe, whereas the corresponding magnetization curves easily saturat e at very low fields. The salient point here is that the GMR is optimi zed without any heat treatment of the specimens, and the results displ ay some unique features of the GMR in this system.