Microscopic origin of the macroscopic magnetic properties of TbFeCoN amorphous thin films

The magnetic properties of TbFeCoN amorphous thin films, made by reactive plasma sputtering, were studied on both the macroscopic and microscopic scales, as a function of nitrogen content. Magnetization measurements showed a very important decrease of the compensation temperature for increasing nitrogen concentrations. The element selectivity of x-ray magnetic circular dichroism and M{umlt o}ssbauer spectroscopy enabled the rare earth (RE) magnetic contribution to be discriminated from the transition-metal (TM) contribution. The macroscopic effect of nitrogen insertion 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 system. {copyright} {ital 1997} {ital The American Physical Society}