EFFECTS OF ANNEALING ON THE MAGNETORESISTANCE AND STRUCTURE OF FE CR(110) SUPERLATTICES/

We have performed magnetotransport, magnetization, and structural expe riments on sputtered Fe(30 Angstrom)/Cr(12 Angstrom) (110) superlattic es that were annealed at temperatures up to 400 degrees C. Interesting ly, their giant magnetoresistance (Delta rho) is enhanced at intermedi ate temperatures, and strongly decreased at higher temperatures. If no rmalized to the antiferromagnetic coupling fraction of sample, the mag netoresistance increases over the entire annealing range. From low-ang le x-ray-diffraction measurements, the enhancement of Delta rho arises from an interface redistribution because of either a slight interdiff usion, less correlated interfaces, or both. Further annealing causes e xtreme interdiffusion that is detrimental for the magnetoresistance be cause of a loss of antiferromagnetic coupling.