Microstructural evolution of NiFe/Ag multilayers studied by X-ray diffraction and in situ high-resolution TEM

X-ray diffraction and in situ high-resolution electron microscopy experiments have been performed to study the effect of annealing on the microstructure of permalloy/silver multilayers. Both techniques show that the silver diffuses into the permalloy grain boundaries creating so-called ‘silver bridges’. This bridging is expected to be responsible for the giant magnetoresistance effect observed at low fields in these devices. Moreover, unexpected permalloy diffusion and recrystallization have also been observed in the in situ TEM experiments.