STRUCTURAL EVOLUTION AND MAGNETIC-BEHAVIOR OF CO AG MULTILAYERS SUBMITTED TO THERMAL ANNEALING/

We report on the structural evolution and the magnetic behavior of the Co/Ag multilayered films deposited in a UHV chamber at room temperatu re, submitted to 10 min thermal annealing at temperatures ranging from 100 to 600 degrees C. The structural characterization was performed u sing X-ray diffraction and X-ray absorption spectroscopy techniques. M agnetoresistance and magnetization measurements were used to study the evolution and magnetic behavior of the samples. The results show that , besides the roughness;It the interfaces and the structural disorder of the Co layers, the as-deposited sample has a compressive stress at Ag-Co interface originated by the difference between the surface energ ies of Ag and Co. After annealing at 400 degrees C, there is a breakup of the layers accompanied by a relaxation of the stress and defects a s well as partial crystallographic ordering of the Co clusters. The ro om-temperature magnetoresistance change from anisotropic magnetoresist ance to giant magnetoresistance with a sharp maximum, reaching 4.5%. ( C) 1998 Elsevier Science B.V. All rights reserved.