MICROSCOPIC ORIGIN OF THE MACROSCOPIC MAGNETIC-PROPERTIES OF TBFECON AMORPHOUS THIN-FILMS

The magnetic properties of TbFeCoN amorphous thin films, made by react ive plasma sputtering, were studied on both the macroscopic and micros copic scales, as a function of nitrogen content. Magnetization measure ments showed a very important decrease of the compensation temperature for increasing nitrogen concentrations. The element selectivity of x- ray magnetic circular dichroism and Mossbauer spectroscopy enabled the rare earth (RE) magnetic contribution to be discriminated from the tr ansition-metal (TM) contribution. The macroscopic effect of nitrogen i nsertion in TbFeCo amorphous thin films was found to be mainly due to a progressive opening of the mean angle of the conical distribution of the Tb moments. Mean-field calculations confirm the prominent role of the RE-TM exchange interactions in the magnetic behavior of this syst em.