Recording Characteristics of Magnetooptical Media with Auxiliary Magnetic Layer

The purpose of this study is to investigate the leakage field from the auxiliary layer to the recording layer in an exchange-coupled multilayered magneto-optical medium. In order to estimate the leakage field, test media, in which the auxiliary layer was deposited on the recording layer with a nonmagnetic layer intervening, were prepared. The leakage field was determined as the difference in the threshold external fields for two different initial magnetization directions in recording tests. The experimental results were in good agreement with numerical calculations, in which single-domain nucleation was assumed. The leakage field was found to be proportional to the change in magnetization at the heated spot. It was also found that a leakage field of about 200 Oe is generated in the auxiliary layer with a change in magnetization of 150 emu/cc.