Structural and magnetic studies in amorphous TbFe films

Abstract

We have studied the effect of argon pressure ( p Ar) on the magnetic and structural properties of r.f.-sputtered amorphous TbFe films. For films deposited at 5 < P Ar < 7 mTorr (type I), the hysteresis loops are perfectly rectangular and other magnetic characteristics are similar. However, when p Ar is higher than 8 mTorr (type II), the loop gets rounded with a distribution in the wall nucleation field and with a coercivity much higher than in the type I films. The structural studies show that type II films have a microcrystalline feature whereas the type I films are featureless. The electron diffraction studies reveal in the as-prepared films of the type I, the presence of two zones without an interface, as has been reported by others with fluctuation in composition. We discuss in detail the effect of heat treatments on the evolution of the structural parameters in both types of films. It is concluded that under our experimental conditions increasing P Ar above 7 mTorr leads to deterioration in the properties of technological interest.