Properties of amorphous TbFe and GdFe thin films for perpendicular recording

The recording properties of magnetic media are closely related to their magnetization process but this process can seldom be directly observed. In this paper the relation which can be found between the perpendicular recording properties of amorphous TbFe and GdFe alloys and their magnetization processes as observed by magnetooptics is reported. In the Case of TbFe the Mr/Ms ratio is a function of the coercivity and the maximum recording density DLis a growing function of Mr/Ms. On the other hand DLdepends on the rotating speed of the disc when writing. It is shown that this property can be related to the magnetization process of TbFe which is time dependent. GdFe media present a square hysteresis loop even if the coercivity Hcis low. DLis a decreasing function of Hc. The domains nucleation process and the domains wall motion were observed by Kerr effect. The behaviour of the DL(Hc) function is derived from these measurements.