LAYER-BY-LAYER DETERMINATION OF COMPENSATION TEMPERATURES OF TbFe LAYERS IN TbFe/SiO COMPOSITIONALLY MODULATED FILMS

The compensation temperature of each TbFe layer in a TbFe/SiO compositionally modulated film, which is composed of thin amorphous TbFe layers and interposing SiO layers between them, is determined through measurement of the temperature dependence of magnetic Kerr hysteresis loops. The difference in coercivity of TbFe layers in the film is attributed to the difference in compensation temperature. The nearer to substrate the TbFe layer is, the lower the compensation temperature it has. This is explained by a slight change in Tb concentration or effective Tb concentration. The latter could be caused by a change in microstructure of the TbFe layers from layer to layer, which results in the change of magnetic structure and/or degree of oxidation of the TbFe layers.