STRUCTURE AND MAGNETIC-PROPERTIES OF COMPOSITIONALLY MODULATED TB-FE THIN-FILMS

Amorphous Tb-Fe compositionally modulated films (CMFs) with alternatin g ultrathin Th and Fe layers were sequentially deposited in a multitar get r.f. diode sputtering system. All of the Tb-Fe CMFs, except those with small Tb content, exhibited a large perpendicular anisotropy. Com pared with alloy films, the Tb-Fe CMFs exhibited anomalous structural and magnetic properties such as a compensation composition with increa sed Tb content, higher Curie temperatures, and an extension in the com position range of stable amorphous films to higher Tb contents. The at omic arrangements in this layered structure were modified by a variati on of deposition parameters such as layer periodicity, substrate bias and composition. The primary factor responsible for the anomalies appe ared to be the alignment of a strong atomic Tb-Tb and Fe-Fe pair distr ibution in the layers of the CMF.