they have been able to achieve a carrier to noise ratio (CNR) of 60 dB (v = 0.5 MHz, bw = 30 kHz, u = 10 m/s). By depositing the same layers on glass substrates the CNR dropped to 50 dB. Most papers in the session on magnetooptical recording materials were devoted to multilayers (or layered structures) consisting of alternating Co and a nonmagnetic metal e.g. Pt or Pd, each individual layer having a thickness of only a few atomic layers. Ochiai, Hashimoto and Aso (Sony) reported on the magnetic and magneto-optical properties of Co/Pt and Co/Pd ultrathin multilayered films. Tsunashima, Nagase, Nakamura and Uchiyama (Nagoya Univ.) discussed the possible role of magnetostriction in Pd/PdCo multilayers. Zeper, Greidanus and Carcia (Philips-Du Pont) were the first to report on thermally written domains and recording experiments in Co/Pt multilayers.
In thin (20nm) films they obtained a CNR of 53dB ( v = 1.0 MHz, bw = 30 kHz, v = 5 m/s). This value approaches the CNR-values obtained in GdTbFe thin films. Multilayers of Co and Pt offer the advantage of increased magneto-optical efficiency in the blue, an important feature for future higher density recording. Furthermore, they are very resistant against corrosion and oxidation and there is no need to apply protective layers. The application of multilayers for magneto-optical recording is an exciting possibility, and increased activitity in this area is anticipated.
In this short report it is impossible to review all subjects discussed at the 1989 INTERMAG.