SPUTTERED GARNET MEDIA FOR MAGNETOOPTIC DATA-STORAGE

In situ crystallized Bi,Ga:DyIG and Ce,Ga:DyIG films were deposited on GGG substrates by rf sputtering. The films had single-crystal-like columnar structure, which resulted in low media noise. The films showed square hysteresis loops with large coercivity, the perpendicular anisotropy being ascribed to the large negative magnetostriction of DyIG. The compensation temperature of Ce,Ga:DyIG films changed drastically depending on residual oxygen in the sputtering chamber, and this unique phenomenon was attributed to the site preference of Ga. Furthermore, it was found that the main contribution of Faraday rotation in the Ce-substituted samples was due to Fe in the tetrahedral sites. Dynamic recording was performed using an Ar ion laser, with CNR's of 57 and 48 dB being obtained for Bi,Ga:DyIG and Ce,Ga:DyIG, respectively. The problem of write noise still remains for Ce,Ga:DyIG. © 1990.