AES and XPS Studies of the Chemical Effects at the Magneto-Optic/Dielectric Interface

ABSTRACTThe chemical stability of magneto-optic structures of sputter-deposited SiO, SiO2, or Si3N4/TbFeCo/SiO, SiO2, or Si3N4 was studied in detail. The degradation of the magnetic properties of the TbFeCo film have been correlated with the oxygen content within the film as determined by Auger and RBS. Auger and XPS depth profiles have revealed that for oxygen containing dielectrics the preferential oxidation of terbium is responsible for the observed differences in coercivity. Reduction of the dielectric at the SiO/TbFeCo interface, along with diffusion of oxygen into the RETM film, have been observed. The Si3N4/TbFeCo structure shows no evidence of either interdiffusion between the layers or oxidation of the TbFeCo film. From our investigation we conclude that Si3N4 is a superior dielectric for quadri layer structures in magneto-optic media.