The thermo-magnetic writing and erasing properties and Kerr rotation angle of amorphous TbFe thin film

The compositional dependences of writing, erasing and reading properties of amorphous TbFe thin film were examined in detail. As a result, there was marked differences between Fe-rich and Tb-rich film. That is, the external magnetic field necessary for writing was generally weaker and less dependent on composition in Tb-rich film and the composition range where erasing could be performed by the field of the same intensity as in writing was wider in Tb-rich side. Kerr rotation angle was measured in two different methods and the scattering values between them were observed in Fe-rich film, while there was no significant difference in Tb-rich film. The origins of these compositional dependence were explained by the differences of temperature dependences of Msand Hcbesides the compositional dependences of rectangular ratio and Msitself. The effects of the adding third elements to TbFe in Kerr rotation angle and minimum writing laser power were also measured. As a result, it was found, among some elements examined in this study, that Sm had effects of not only decreasing writing power but also increasing Kerr rotation angle in some degree.