Aging phenomena in TbFe thin films

Abstract

The aging phenomenon of amorphous TbFe thin films when protected with a SiO2 layer is studied by plotting the hysteresis cycles of the films at various time intervals. The changes observed in the coercive field are related to the changes in the Tb content of the layer. It is suggested that Tb atoms, in spite of their size, can move easily in the layer and tend to migrate out of the amorphous TbFe film. This hypothesis is confirmed by the differences observed in TbFe films deposited on pure Tb underlayers of different thicknesses and by Auger profiles carried out on aged samples.