Rachid Sbiaa

Relaxation time and thermal stability in magneto-optical recording media

The time dependence of the magnetization process in amorphous TbFeCo thin films and (TbFeCo/Pt) multilayers is studied. By assuming a Gaussian distribution of relaxation times for magnetic aftereffect, the non-Arrhenius behavior of the magnetization decay is found in almost all samples. From a fitting of experimental data one can determine the mean value of relaxation time /spl tau//sub 0/ and also its width /spl Delta//spl tau//sub 0/. The multilayers of TbFeCo/Pt show a high stability compared to single layers of TbFeCo with also a small activation volume.

Magnetization process and thermal stability in longitudinal magnetic recording media with a stabilizing layer

The thermal stability in an exchange coupled CoPtCrB trilayer structure medium (TL) is discussed and compared to that for the corresponding single layer (SL) medium. The time dependence of magnetization shows a nonlinear behavior. The magnetization decay rate is found to be reduced in TL when the applied field is close to the coercivity. The DC demagnetization (DCD) reversal mechanisms are investigated by magnetic force microscopy. It is observed that for the reversed field close to remanent coercivity of the TL and SL, very coarse magnetic structures appear.

High density magneto-optical recording using solid immersion lens with magnetic field modulation

A near field optical technique based on combined supersphere solid immersion lens (SIL) with magnetic field modulation (MFM) recording is described. A better resolution is achieved by using SIL with MFM recording in comparison with light intensity modulation. A recorded mark as small as 0.3 /spl mu/m/spl times/0.2 /spl mu/m could successfully be detected. These marks were readout by the SIL head with a typical signal to noise ratio value of 36 dB. The present study demonstrates the capability to achieve a very high areal density beyond 20 Gb/in/sup 2/.