Giant magnetoresistance and microstructures in CoAg granular films fabricated using ion-beam co-sputtering technique

The correlation between the GMR effect and the microstructures in ion-beam co-sputtered CoAg granular films was systematically studied. The highest magnetoresistance was observed in Co₂₂{Ag}₇₈$ samples. It is sensitive to the annealing treatment and to the size of the cobalt granules. The microstructures of the sample were studied by a variety of structural techniques. HREM provides a clear two-dimensional image of as-deposited Co₂₂{Ag}₇₈$ samples. Real-time observation of TEM together with FMR indicates that the shapes and sizes of cobalt granules evolve primarily in plane during the annealing process. {} 1996 The American Physical Society.