Microstructure and magnetic properties of Ag/Fe/Ag pseudo-sandwich nanogranular films

Nanogranular Ag/Fe/Ag films were prepared by magnetron sputtering from a silver and an iron target onto glass substrates at room temperature and subsequent in situ annealing. The structural and magnetic properties of the films were investigated as a function of silver layer thickness and annealing temperature. X-ray diffraction shows the Fe(110) peak is formed in all the samples. Vibrating sample magnetometer measurements indicate that the magnetic moments lie well perpendicular to the film plane. Coercivity reaches the maximum in the sample annealed at 500 degrees C for 30 min with 3 nm Ag layer. A scanning probe microscope was used to scan surface morphology and magnetic domain structures. In as-deposited samples the average grain size and the average roughness is smaller than that the annealing samples. After annealing, the grain size is larger and the contrast of domains increases, but the domain size becomes smaller.