MOSSBAUER STUDY OF LASER-ANNEALED Tb-Fe FILMS FOR MAGNETO-OPTIC RECORDING

Abstract

Mossbauer spectroscopy and magneto-optical (MO) studies of thin amorphous TbxFe100_xfilms (11<x<34 at.%), subjected to the pulsed laser annealing, were carried out. The TbFe films (160 nm thick) were RF-sputtered onto glass substrates; both sides of the films were passivated with SiN layers (85 nm). Both Mossbauer and MO measurements confirmed that in the successively annealed films spontaneous magnetization is well aligned 57 along the film surface. The evolutions of hyperfine field distribution at Fe and MO data reveal that the laser annealing results in the atomic ordering of TbFe alloys. The crystalline phase of a-Fe appears in the Fe-rich films subjected to laser annealing.

Directional effects of heavy-ion irradiation in Tb/Fe multilayers

“…It shows, regardless of the ␣-Fe peak centered at 33 T, a bell-like shape structure characteristic of an amorphous alloy, with a maximum centered at 18 T. Furthemore, the mean isomer shift ͗␦͘ and the mean hyperfine field ͗B hf ͘ ͑Table II͒ evolve towards the values of the amorphous FeTb alloy ͓͗B hf ͘ϭ18 T and ͗␦͘ϭϪ0.08 mm s Ϫ1 ] with the same nominal Tb composition of the multilayer (X Tb ϭ0.19). 16,17 Thus, the loss of crystallinity of Fe layers is associated with the formation of an amorphous FeTb alloy, indicating a strong atomic mixing and amorphization induced at the interface in the vicinity of the ion path. 18 Figure 2͑c͒ presents the Mössbauer spectrum of the 57 Fe probe layer irradiated with ions coming from Fe to Tb layers.…”