INFLUENCE OF NB, PT ADDITION FOR THERMAL- STABILITY OF TBFECO MAGNETOOPTICAL RECORDING FILM

The relationship between the thermal stability and the magnetic charac teristics of an amorphous magneto-optical recording film was studied b y using TbFeCoNb and TbFeCoNbPt films with same curie temperature and the compensation temperature. The film with small decrease of the perp endicular anisotropy of addition of elements such as Nb, or Pt and Nb, had a high thermal stability. However, the perpendicular anisotropy o f the film with the addition of Pt and Nb decreased more than 1/10. Wh en the film was annealed at 250-degrees-C, the perpendiculer anisotrop y was disappeared. From the results of Auger electron spectroscopy, th e differential thermal analysis, the X-ray diffraction method and the magnetic torque measurement, this change of the perpendicular thermal anisotropy is not caused by the crystallization of the recording film or the oxidation of the film, but by the structure relaxation. As a re sult, it is found that the important factor for the thermal stability of the film is to control the change of the perpendicular anisotropy w ith less than the desired constant value.