Mossbauer studies of small amorphous particles in granular films

Granular films consisting of finely dispersed Fe82B18amorphous grains in a Al2O3matrix are studied by Mossbauer spectroscopy and electron microscopy. The samples are prepared by cosputtering with rotating target. The particle diameters vary between the limits 40 and 70 Å depending on the samples. The hyperfine field distribution becomes wider as the particle diameters decrease. The superparamagnetic properties are studied. It is shown that the value of anisotropy energy is high and is principally due to magnetoelastic energy.