The magnetoresistance and microstructure of Fe-xCr-10Co alloy thin films

Large negative magnetoresistance (MR) is observed in Fe-xCr-10Co (x=10,20,30,40,50,- 60,70, and 80 wt %) ternary heterogeneous alloy films prepared by the IBS (ion beam sputter) deposition process. All the as-deposited films consisted of the a phase alone. After aging treatment, the alpha phase is decomposited into two phases: the alpha(1) (Fe-Co rich phase) and alpha(2) (Cr rich phase). In the granular alloy, the GMR effect is obtained by virtue of the interface scattering between alpha(1) and alpha(2). After isothermal aging at 400 degrees C for 1 h, the largest MR of -27% appears around the Cr content of 60 wt % at 77 K and 14 kOe. The MR ratio of Fe-50Cr-10Co and Fe-70Cr-10Co is -12% and -20%, respectively, at the same condition. The MR ratio is also obviously effected by the Cr (or Fe) content in the alloy system. (C) 1996 American Institute of Physics.